It's only really a problem if your software isn't designed for it. Most of the problems people had with DOS memory protection issues were due to the lack of standardization around memory management. Similarly so with Windows 3.x, running DOS programs from Windows on top of DOS was never going to work well. Even Windows95 had its problems.
On the Amiga it didn't have this problem. There was AmigaOS and that was it. The base hardware was for the most part tightly coupled to the OS and the architecture was designed to provide standardised mechanisms for accessing hardware that were fairly stable. The Amiga had different stability issues of course, but my A4000 manages fine without memory protection despite having a full MMU on-board.
I mostly meant in terms of security in the modern age. Few people in their right mind (in the realm of computing enthusiasts) would use AmigaOS as their only daily driver because of it. There’s a reason all modern OS architectures have memory protection as a core feature. In 2020 you really don’t want any process on your system to be able to access, let alone clobber any other process space.
On the Amiga it didn't have this problem. There was AmigaOS and that was it. The base hardware was for the most part tightly coupled to the OS and the architecture was designed to provide standardised mechanisms for accessing hardware that were fairly stable. The Amiga had different stability issues of course, but my A4000 manages fine without memory protection despite having a full MMU on-board.