I ferment them for a few reasons......
1.) Just because I have them and wanted to try it.
2.) I do think the fermented peppers taste different - especially blended with something like fermented carrots.
3.) My fall season is crazy busy with teaching/coaching and I just don't have a ton of time to really do much with my peppers as they come ready ...... fermenting the peppers is sort of a way to keep them "fresh" without freezing them..... and without needing to really do anything with them at the time of harvest.
4.) In regard to boiling..... I really don't care about any "probiotic" type thing with hot sauce. We do a lot of Kraut, pickles, and other fermented veggies that we can get the probiotics from..... hot sauce is a condiment and just using a splash here and there..... so, boiling it for preservation and to reduce/thicken the sauce is really just about getting the sauce to where I want it. The vinegar and salt I add is just a touch here and there to taste.
I use a 5-7% type brine. Personally, I think green jalapeños turn out kind of gross. If you are going to do it - Cayennes are #1 in my opinion. And then perhaps blend in red jalapeños and habaneros as desired.
I do a lot of my pepper ferments in 1 quart mason jars so that I can do a jar here and there as I harvest them, and I can then keep the jars dedicated to one type of pepper and blend them later if I want or make a single pepper sauce if I want.