As you say, being a taildragger or glider pilot doesn’t by definition make you a better pilot overall. But I do believe getting some glider (which I have) and taildragger (which I haven’t – there really aren’t many of them to train in in my local area) training will help. It’s not necessarily so much the type of training you do, so long as you get training in a type of aircraft you have little-to-no experience in, because more unique training, I think, makes you a better pilot (or at least better appreciate the type of flying you do do). For that matter, helicopter training will make you a better fixed-wing pilot too (I found it actually made me much more comfortable with short-field takeoffs in fixed-wing planes).
This is a companion discussion topic for the original entry at https://www.avweb.com/features/reader-mail/top-letters-and-comments-october-9-2020