Aptoide itself is a framework like Facebook or second life etc
not a single store like Google play , Apple apps , galaxy store, Amazon store. It's a apps archive from individual users of it. the apps apk could be on users aptoide app on thier devices. If that users device is off ...... you all get it , I'm sure you need the store address or id, each store has its own parameters of sharing and avariability in App-To-Ide
The arguments of saying I went there to find qpp x, its not there, are akin to saying I went to second life , and I didn't find what you said was there .
The individual user app archives are known as stores. can it be more dangerous than buying app from original development ? Depends on the user. SL has allot of dangers too, a certain risk is accepted to use things.
in a nutshell millions of people use aptooide to archive and share thier own apps.