If you are talking about altcoins that has future, i wont hesitate in telling you that ETHEREUM, NEO, XRP, XLM, BNB, MONERO AND NEO are some of the altcoins that have a bright future
As speaking of their functionality - yes, it is needed, their potential is incredible.
Still, it is rather clear that as time goes by and global regulation standards will be introduced - privacy coins would be forced to move to the shadow. Already in Japan, no exchange can get a license if it has any privacy coin listed. Even in the UK, some exchanges are already delisting them or are forced to apply a much wider scope of verification of people buying them.