If Bitcoin is fine trading with around 16,000,000 coins, then why does any other coin need more?
Total coin supply is just a matter psychology... when the total coin supply is too big, you tend to think of a single unit of said coin as some cheap stuff, like DOGE.
If its more rare, you find it more valuable per coin and expect a bigger price.
Of course, this is irrelevant if the coin is useless.