You can take this advice or leave it, but if you're not going to stay current in a tailwheel aircraft and fly one regularly, I think you're just setting yourself up to be a ground-loop statistic.
Sure, get the endorsement but if you're going to mostly fly a nosedragger, I don't know how you're going to stay on your game to fly it "every so often".
I personally think a glider rating has similar value in "connecting feet to brain" and would tend to go that route first. Or be very cautious with a tailwheel endorsement and budget to regularly go up with a CFI in it until I knew all synapses were hard-wired to appropriate tailwheel responses, which would mean significant recurrent time in a TW aircraft every so often.
Just an opinion.
Don't mean this as a criticism, but I think a lot of you guys with loads of experience may have forgotten the thrill of learning. I was on home leave and took a few lessons. I was only going to be home for 2 weeks and seriously pondered getting the tail wheel endorsement. Heck, I was going to be out of country again for a year and knew I wouldn't use it, but it was fun to fly a different kind of plane, land in different places, face different challenges. I'm a bit disappointed I didn't make it happen.
I've lost the photo, but had it as a screen saver for a while. Instructor took it and you could see part of the Cub wing, part of me and a beautiful bit of country side. I still remember when he took me to a paved runway and had me just work the pattern. Then we switched to cross wind landings and it felt totally different.
At the time, I owned and had been flying (until going overseas) a Velocity. Wasn't reasonable to unpickle the plane for a few weeks and besides I was pretty rusty with no way to get a local Velocity check out. The few flights in the Cub were HIGHLY memorable. The Cub is my daughters favorite plane "in the whole world" and now she knows I flew one. Pretty neat contrast to the Velocity - couldn't see the instruments, door open, airspeed control by sound/feel, completely awesome.
I'd encourage you guys to encourage us. You can throw in a "you need to be REALLY careful if you don't stay current" and maybe even a "you'll become a statistic if you think you can fly a tail wheel just a few times a year", but new experiences are why many of us picked up GA in the first place. I'd love to get a tail wheel endorsement and a sea plane rating. May not use them for years or maybe even ever again, but I want to do it.
So Kim, I'd encourage you to get the endorsement. It is a BLAST to fly a tail dragger. Go out and do it, check it off the bucket list, do it and enjoy it. Where you are with your license now is basically flying just to fly. The instrument rating is rewarding and challenging and will increase the utility of your license, but the tail wheel endorsement is plain old fun.