The game studio I worked for hated side loading. It's often used by fake sites (including crypto mining and identity theft sites) to offer "free" apps which are really just APKs from legitimate publishers.
The user is left with an app that won't be updated or get bug fixes and may not even work at all because of ongoing changes in the game server and its APIs.
Our game was entirely free to play and there was no way to get any additional stuff by using a side loaded APK from someone else.
To make matters worse, users put themselves at risk when they enter their personal information like passwords and payment info into these illegitimate APKs as it can be captured by modified versions of the apps, which is why folks distribute them.
The user is left with an app that won't be updated or get bug fixes and may not even work at all because of ongoing changes in the game server and its APIs.
Our game was entirely free to play and there was no way to get any additional stuff by using a side loaded APK from someone else.
To make matters worse, users put themselves at risk when they enter their personal information like passwords and payment info into these illegitimate APKs as it can be captured by modified versions of the apps, which is why folks distribute them.