And, stupid question, what can these not do such that someone would still use a non-stainless as this kind of daily driver?
Re-reading your Qn, I realise that the second half has only been obliquely covered.
Stupid Qns are the ones you haven't asked yet, so this one no longer is stupid.
R2 (and SRS 13/15) are good knife steels. Long edge retention, not ridiculously difficult to sharpen or deburr. So "why use carbon steel?" is a good Qn. There are several different reasons you might consider a carbon steel knife:
1) Easier to sharpen and deburr.
2) More pleasant to sharpen, with better sharpening feel.
3) Maximum sharpness is greater.
4) Patinas are pretty and give character to the knife.
5) May be easier to thin.
6) It's older technology which works and carries a bit of je ne said quoi. (Maybe describe it as character? romanticism?).
7) It's cool to look after a precision instrument that you can't get away with abusing.
I live in a climate so dry that the landscape tends to incinerate itself every Summer, so it's not too hard to look after carbon steel. I think I'd have a few more stainless knives if I lived in Singapore.
There are some stainless steels which are a little more carbon- like in their sharpening performance. AEBL and to a lesser extent Gingami3/ Ginsanko come to mind.
I don't know how semistainless holds up in Singapore's humidity. If it copes well, it offers a lot of benefits. As long as you don't leave it lying around wet or dirty, it won't corrode in normal use (at least in my climate). Maybe patina a bit over time. If well heat treated, it I can be almost as nice to sharpen as carbon steel, gets almost as sharp and has pretty decent edge retention. Some specific examples of well HT'd semistainless that I am familiar with include:
1) Yoshikane SKD (apparently their SLD, which has higher Cr, almost stainless is also pretty good. Mashashi trained at Yoshi and his SLD is also pretty good).
2) Whatever the semistainless in Gesshin Gengetsu is.
3) Sukenari's YXR7. A lot like SKD but tougher.
4) The semistainless in the old Itinomonn (no longer produced).
Those knives all have the benefit of being very good cutters as well.
Edit: a note on nomenclature of SKD and SLD:
SKD-12 is very similar to AISI A2. Yoshikane calls these knives "SKD". 5-6% Cr.
SKD-11 is also known as SLD and is similar to AISI D2. Yoshikane calls these knives "SLD". 12-13%Cr (almost stainless).