cryptocurrencies have value, you may call some of them a currency even, specially bitcoin. and when money is involved lots of scams will follow, from people who are always out there wanting to make money by having their hands in other people pockets.
and it is not just Google Play or App Store, it is all kinds of scams. not so long ago we saw how the scammers used a fake web wallet for bitcoin gold and used desperate people trying to get the airdrop to rob them blind from both bitcoin and bitcoin gold.
I saw that video in you tube on how to claim bitcoin gold requiring you to fill up some information including the private key or seed. People who are not aware of what is happening immediately fill up the form excited to claim their bitcoin gold and end up being scammed because they just want free coins immediately without even searching further if that is the right thing to do.
With the increase of value of cryptocurrencies is the increase in numbers of scammers as well so we should always do some due diligence before doing something like downloading an app. I am not of one of those that have downloaded the fake Poloniex app but maybe if I am still trading in Poloniex then I may have downloaded it as well which would be my fault then. This is an eye opener to always be on guard when it comes to dealing with our funds.