Pretty sure the altcoins isn't worth the risk of using their new exchanges lol. Not to mention that even big exchanges themselves afaik host similar types of events, if not the same (not that I participated in any of them). In addition, you should prefer reputable exchanges to new ones regardless of the amount of giveaways they do. It's REALLY normal for some shitcoins to be given out thinking that it was priced at X amount but turns out it was actually Y amount at the time you'd received it lol.

If you wanted to earn some altcoins, there's probably a bunch of airdrops and events out there that don't involve storing your money in their exchange.