I wonder how this download gets counted. From what I recall, Google counted unique account/device IDs for each download. So 10k downloads mean 10k unique downloads, although scammers can easily fake this by running multiple instances of emulators or paying someone with peanuts to download their apps. That being said, 200k is a high number. Some legit apps that I know of never reached that number as far as I can tell, but that probably happened because the dev put a direct download link on their website/GitHub. As for 500k, probably only games can reach that number easily within a month or so. CMIIW.
Scammers have ways to count their downloads unique, I am not aware of the full method, but they can hire someone or some devices or can run ads to get fake downloads. There are many people providing such services to give you fake downloads, and each of them get's counted. And you are right a crypto app might not get 200k to 500k quickly, but games can.
But I don't trust any new crypto apps that easily and advise everyone to do the same because they are new, and don't value their customers now. At least we don't know from their any action if they care about their users or not. So, just to remain safe, don't connect your main accounts with them even if you download them.