Most people would probably consider it quite morbid to have coffins lining the halls of their schools, workplaces or public areas. [...]
Most people? First of all, these are dwarves. Second of all, there are plenty of examples round the world (or in history) of ancestor veneration through the viewing of their remains in everyday locations. Some quite regularly for most people, although others only for the most prominent individuals of course. And then there's the display of the non-venerated (enemies, criminals... and sacrifices of various kinds if they don't also get a kind of "venerated" flag in that particular culture).
Personally, for better or for worse my fortresses a run without the nominal disregard for life. Nobles get their desired tombs (as might other significant ones) but I rarely run a fortress long enough for old age to kick in[1]. I've never yet carved a slab (though I have filled the odd coffin, since slabs came out), although I made some blank ones when they first came out and lined one of my roads with them, not really knowing what else I was supposed to be doing.
Back in times prior to DF2010, I used to regularly lay out 5x5 rooms on the lowest level of the map (certain other features allowing) and give most dwarves a tomb of their own (regardless of nobility or need, although I might have needed to expand or decorate for some who wanted much better). But back then I also used to need them a lot more than I do now, sometimes at a greater rate than I could outfit them with their living ownership of such a room.
[1] My .31.25 fort, started within a few weeks of that version coming out, has been micromanaged so much, and thus in the paused mode, that I'm still only six game-years in. None of my 200-ish dwarves has died of old age, and my defences and more dynamic defensive measures are (<knuckles tapped to head> knock on wood) pretty much able to handle to anything but the flying-mounted enemies that I haven't yet encountered[2], thus no deaths.
[2] And I've got archers and mobility, and besides which I have the ability to make ground-path closure that rather spoils deliberate and direct flying over.