i was able to download the app from an external link
I hope that you downloaded the app using link on Poloniex website.
Google closely checks the apps available on its store, so you are less likely to get a malware with an app coming from this source.
I wish that were true. I have reported dozens of fake wallets on the Play Store, and it usually takes them weeks to remove them. The problem is that they don't manually check these apps; instead, they use an automated system. This often results in fake apps appearing on their platform.
It happens on the Apple Store as well, but much less frequently.