Yesterday, the popular third party android app hosting site apkpure's android app was infected with trojan.
Everyone who downloaded their official app or had auto updates turned on was fucked.
Of course, neither is Google play 100% safe but reduces the likelihood of infected apps.
Kaspersky print: https://www.kaspersky.com/blog/infected-apkpure/39273/amp/
Sorry, but why download apps from a third party to your smartphone, where basically all private information about you is stored when you can get the app from the official Play Store at the same time, where before uploading a security check is done by Google? That is absolutely stupid! It's good that you warn here, but downloading apps from apkpure and other similar sites is only recommended for testers, developers and security engineers, never for "normal" users.