As far as im concern, its depend to altcoin on what are they offering. Basically altcoins are 2nd, 3rd or 4th generation blockchain next to Bitcoin. Let say they are more powerful in terms of algorithm they use, scalability, interoperability and etc. Nowadays one of the advantages of altcoin is they tend to make best lightning protocol that can enhance the speed of processing transactions and how they can iteract to other blockchains as well.