In my opinion (!) it comes down to dollars.  There's nothing wrong with having the credential, and it could be seen as a (small) positive for you by some employers.  Just know that USGBC has gotten a reputation as charging for every little thing you want to do-- especially once they get their digital hooks in your contact info.

Some folks have managed to pass the exam without paying for a prep course... though it's probably more challenging these days.

I have the certification and completed it 10-12 years back when it was the thing to do.  I have never used it and don't ever get asked about it on RFP or by new clients.  I do get a lot more interest in passive house certification though.  I would say if you are prioritizing I would focus on Passive House Certification, LEED is good to know but not something I need or feel I would use at any time in the future.

I say no. I'm not certified and it's never been an issue for me. The only time I think it would become an issue is if an employer requires it. I know some do and will tell you that you have to get certified within 6 or 12 months of being hired. They'll also probably have study materials (or would pay for them), and pay for the exam if you pass it. My current employer used to require it, but stopped a number of years ago.

No. my company required everyone above a certain position to get qualifications to meet some quota they felt would demonstrate green awareness. And we all continued never to do anything with it. On the projects which submitted for leed certifications we always recommended a specialist consultant because we had letters after our names but no usable experience to answer reasonable questions the client had about how it works in reality.

 in other words if this is important to you you'll need to look for a job where you can get real experience and build on it. for any other job no architect is going to be fooled and think the extra letters after your name give you any expertise at all. it neither helps nor hurts.

If you have the $250 and the time available, it would be a good introduction into some important elements of environmentally responsible design, which you may not have covered in school, and having a few letters after your name can't hurt. It's a well known program, even if it's rarely used these days.

I also agree with Whistler that Passive House training may be more worthwhile, but it's also much more expensive, and if you don't understand some basic concepts about building, which you likely don't if you only have an academic education, you will not get as much as you could out of the training. It's not a holistic program, as LEED is, but focused on energy use, indoor air quality and occupant comfort. (I'm a Passive House consultant.)

It matters a lot for certain firms - mostly those doing public projects in states that pay a higher % of construction costs for LEED certified projects.  It matters especially a lot in states with mandatory so-called quality-based procurement for public projects, where anybody whose resume is used in the proposal pretty much has to have every certification/accreditation listed as relevant.  But it matters almost not at all in the vast majority of other firms.  

Always factor in the long-term costs and time to maintain any credential you're considering.  A thing to keep in mind is that these days once you get LEED accredited, you need to acquire a certain number of continuing ed credits every 2 years (this wasn't the case for the original LEED accreditation scheme, but it is for LEED GA, and for all the LEED-with-specialty accreditations now.). The majority of the CEUs that you need are general credits that are easy to get for free - lots of online courses that count for AIA continuing ed also count for USBGC.  But there's a requirement for 6 "LEED-specific" credits in each renewal period, and those can start to cost money to keep up.  If you're not getting those CEU's by being a documented member of one or more LEED project teams working on specific credits for those projects, or by writing approved LEED-related content or volunteering for USGBC, then you have to get the LEED-specific credits from approved LEED-specific courses, and there are only a very limited number of free courses for that.  I burned through the free ones after my first 2 renewal periods. Most sponsors aren't interested in jumping through the hoops to get their material approved as LEED-specific for a free course, so now there aren't enough new free ones each period.  So if you're not working on LEED projects on a regular basis then you should budget around $300 every 2 years for the CEUs to keep up this certification after the first 2-year renewal (in addition to the regular $85 renewal fee).  If your employer cares about LEED then most likely they will pay for these expenses, but if they don't care then you may be on the hook to keep up this certification (or you can let it lapse, but they you'd need to retest if you want it back again in the future.)

I agree with those above. You're likely to have a bit of a hard time following it if you don't have some work experience. 

Professionally speaking, my firm has not been asked to pursue LEED for any project since at least 8 years ago (about 500 projects in total). So unless a firm you're interested in requires it, save your money.