By SFF you are talking small form factor? To my knowledge there is only one big player in this field which is Intel NUC and I am not even sure THEY have business support. Thats a big argument for laptops, because you get proper business support compared to niche products like SFF devices.
But maybe I completely missed your point.
A bit late, but wow openbsd developers use their own distro as a desktop, you convinced me. And yes I know it might sound weird but openbsd has a special use case. Its a security focused distribution aimed at developers which want to understand the workings of an OS. Its also used as a base for some router specific operating systems.
Everybody who used OpenBSD on the desktop knows it has its shortcomings compared to any other OS if your workload extends beyond simply checking mails and surfing the web.