The Bugfix release chain may not have the hardware support for the latest models. That is probably why you cannot downgrade lower than the minimum release, as in your other thread.
If I may, I believe that the "mikruser" was suggesting that the proper hardware support be added to whatever is the current "bugfix" chain at the time of that hardware's release, so that if someone bought a hot-off-the-press product, they could elect to run "bugfix" on it instead of "current".
HOWEVER, think about it for a second: the whole point of "bugfix" is "only fix bugs, don't add new features". New hardware support is a feature, is it not? Adding additional hardware support to "bugfix" would require changes at a deep enough level that it could cause an unintended regression/bug even for already-supported existing products.
I don't think this is a good idea.
If a new product comes out that can only run "current", and the "current" chain at the time has a showstopping bug in it that doesn't exist in "bugfix", best strategy is to report the bug to MikroTik Support and wait for the fix to show up in a future version. At least this way "bugfix" won't risk otherwise-avoidable regressions on existing hardware that you are already running it on, plus bugs are weeded out of current and future releases faster (there is always a risk that when someone downgrades to "bugfix" to avoid a bad bug in "current" or "RC" that they won't bother to report the bug that caused them to downgrade).
I know it's probably not what you want to hear...