While mtier may have exaggerated the difficulty of updating from source, "...writing a 20 line script to get notified if the page is updated, that's enough [...] updates are trivial: update, re-compile, reboot" downplays the hassle a little too much. Your procedures are fine if you only have to update one machine, but they are inefficient when you have multiple machines to update. Furthermore, OpenBSD doesn't need a lot of RAM nor disk to run, but to compile is a different matter. This is not a problem (at least for i386 / amd64) for physical machines made in the last 15 years, but is a concern for VMs. IME, w/o X11, OpenBSD (i386 / amd64) runs fine w/ 64 MiB of RAM, but needs 512 MiB of RAM to compile (excluding X11) without swapping.

For my use case, I set up a dedicated builder VM, have it build a full release, then "upgrade" the other VMs with my local build. Although the installer only officially supports upgrading from version N to N+1, IME it seems to work for N -> N "upgrade" as well. This is workable and not too complicated, but it's definitely not trivial.

That said, to me mtier doesn't provide enough value, either. Prior to me setting up a dedicate builder, I probably would be interested, if they provide support past upstream's support period. 1.5 years is not "LTS" to me.