There’s been multiple use cases lined above - for abandoned trails where path visibility and cairning are both poor to intermediate, or for ones where cairns/markers can be seasonally covered etc.
If current trail_visibility as a whole (mix of trail surface and makers) is all we need, then why do we have a separate trailblazed:visibility? Why is the visibility of markers in and of themselves important, but an actual physical path/trail unimportant??
Your argumentation would support the removal of trailblazed and trailblazed:visibility unless you can make a case for why they are more important than there being a physical visible trail surface as they are currently included in trail_visibility. Currently trailblazed:visibility is essentially trailblazed:visibility_if_there_is_no_trail
On my phone so no code wraps, but the point should still stand. At the very least it seems like if we’re keeping trailblazed having a trail_surface_visibility seems reasonable.