If an app such as Pokemon Go isn't available on Google Play store yet, and millions of people download it from apkmirror.com for three days, does that mean during this time Google Play store doesn't want to support or pay for the download bandwidth?
Or does it mean the app is still under verification and Google still has to verify the app? But if so, millions of people still download it regardless.
I am somewhat concerned because if it is the director or CTO / CFO or government officials thinking apkmirror.com is 100% safe and download the app, you never know whether the app is tampered and what the app can be doing. It gives a security hash but even that can be tampered or hacked. If it is Google Play store, at least you know you have Google to stand behind it.
P.S. Niantic announced the update on Nov 1, 2017, and right now is Nov 6 and the update is still not out on the Google Play Store yet. But it has been on apkmirror.com since Nov 1. It doesn't show how many downloads so far, but it could be hundred of thousand of people, if not millions, because the update has bug fixes and also said to allow users to power up Pokemon to level 40, which was affected by a bug since one year ago that only allowed people to power up to level 39. Well, the "bug fix", after one year, turned out, reported by other players, to only allow players to power up to level 39.5, but due to this fix, it could be many users already went the apkmirror.com route to download it.