It's good in theory but in practice you'd need to spend a lot of time and money doing deep audits yourself, both hardware and software. That just really isn't a worthwhile investment for the vast, vast, majority of people.
At the end of the day it all still boils down to trust based on reputation, incentives and oversight. Openness is important but no panacea.
Its silly to advice against reasonable actions like switching to an OS that respects your privacy based on unreasonable standards that aren't met presently anyway.
Don't bother leaving that disease ridden hag covered in boils you can't possibly invest the resources to sequence the full genome of this clean looking young lady over here it all comes down to trust amirite.
Perhaps, but if poor UX prevents a user from using an ostensibly more secure platform, then security of said platform doesn’t enter into the consideration at all.
How many distros are shipping with ASLR now? Last I knew there were still major distros that weren't.
Heck, do the common DEs sandbox their search indexing processes yet, given there's been various vulnerabilities there previously?
Yes, okay, you have control, but when nobody implements relatively basic defence-in-depth mitigations that have been available on Windows (especially) and macOS for over a decade it's just sad and undermines the argument that its security is better.
At the end of the day it all still boils down to trust based on reputation, incentives and oversight. Openness is important but no panacea.