@justdudeone
I think you should read @Ekopalypse arguments carefully.
But let me try to give you a specific example:
I fetch everyday a nightly log from our build server named build_<date>.log. E.g. build_18082019.log.
I open it with Notepad++ and observe it.
I close Notepad++.
I delete the file since I no longer need it locally.
With your proposed solution within a year Notepad++ will remember within its auto-session 365 files that will never reappear again and spend considerable amount of time trying to open each of these files. I will not be aware of this list of files that Notepad++ tries to open in the background (other then noticing that Notepad++ becomes SLOW). The example could be modified to using files over network shares which can be even more catastrophic due to occasional VERY long network timeouts.
Try to be a little less egocentric and realize that Notepad++ needs to balance different requirements of thousands of usage patterns.