I don't use any cleaning apps on my phone. It cleans apps that aren't being used automatically. I think it's like that for most phones nowadays. If you leave an app to run in the background, it will close itself after a certain time.
No, there is no reason to be using them on Android, at least if your using anything past like 10 or 12, I forget. But it has smarter ram management and suspends apps that haven't been used in a while.
No, I don’t. I’ve never really heard of anyone using that. I’ve got an iPhone, and iOS has some built in features where you can offload apps and free up storage space.
Those cleaning apps have no particular use for me. I always view them as nothing more than just graphics. The ones I have used don't clean anything on the phone.
I saw one cleaning app that came as one of the stock apps on my phone. I have never opened it for once in five years of using the phone. I wish it was not a stock app, I would have uninstalled it.