@delta @lyyn @rakoo I think the real reason is because (Android) smartphones want to suspend the actual CPU whenever possible and receive notifications via the less power hungry baseband modem. AFAIK it's capable of maintaining simple TCP connections on a very low level, which is what Google's FCM service is.
Read somewhere a loooong time ago that the reason for that is that some applications were doing stupid stuff like sending packets all the time, essentially having a constant use of the network, just to check for new content. When all applications do that, each on its own clock, the battery doesn't last very long.
Which is a shame because a proper application without FCM and proper implementation is virtually invisible. Keeping a TCP socket open costs nothing, even from an app. But it's always the same: if the consequence is that the battery is bad, then the one that is blamed is Google/Apple, not the app maker.
@delta @lyyn
Read somewhere a loooong time ago that the reason for that is that some applications were doing stupid stuff like sending packets all the time, essentially having a constant use of the network, just to check for new content. When all applications do that, each on its own clock, the battery doesn't last very long.