The Play Store was riddled with scam apps last time I used it. Be it fake apps that pretend to do something while doing at best nothing ("system optimizers", "antivirus" apps) over user data mining apps (often targeted at children or young people) to hundreds of clones of commercial or open source apps - you do not have to search very long to find the real scams.

Making sideloading harder has only one goal - growing the wall around the garden a bit higher, piece by piece, layer by layer, while everything within slowly grows more toxic.