Bottom line, people shouldn't need to use an exchange to go through 5 altcoins because each has a single property that's useful to them.
Exactly. Specialization is only good when it is necessary. Crypto communities like to jerk each other off about how special they are, but a lot of these specializations are arbitrary
If anything, the only real benefit these other coins have imo is to later have their specializations brought to Bitcoin somehow. With a few exceptions like LBRY.