There are so many coins, but many of them just a copy of anothers. Why they waste their time for nothing?

Well people do that because they need to store them and make worthy of buying. Coins like Paragon, Ripple and Lisk are too good in the market.
That's what many project scammers do. they made an ico with the same specifications as the other projects.
with the aim of reaching crowdfunding and then scaming many people. I hope we can avoid coins like that