In my opinion sub assets just complicate things. Why not just put these assets into labelled folders? I think this would be MUCH simpler. Think about UNIX. Everything is organized into files. There are no “sub files”, just files.
depends sometime folder structure is easier to navigate
That is not what a subasset is.
Stop offering help to people when you are new yourself and are getting things wrong a lot. This is just one of many many threads now that I have come across you offering incorrect advice or getting confused as to what is being spoken about. Sorry but, you have been around for 3 weeks, your in no position to give people help on using the engine. Your offering help and at the same time asking beginner questions in other threads. Your bad advice is going to end up wasting peoples time, so only offer advice on topics you have experience on.
On windows platform it is entirely possible to hit MAX_PATH limit this way which is still measly 260 characters unless you use nt paths or mess with registry.
https://stackoverflow.com/questions/27680647/does-max-path-issue-still-exists-in-windows-10
Additionally, name clashes and difficulty of moving things about.
Unity bakes assets upon build anyway, so making “subcontainers” does make sense.