Yeah, I think so too now that I read some documentation about it. It appears that the main issue with the spinlock pattern is that it inhibits "a severe performance penalty when exiting the [spinlock] loop because it [CPU] detects a possible memory order violation." [0].

~10 years ago, on Haswell, it took ~9 cycles to retire, and from Skylake onward, with some exceptions, it takes a magnitude more - ~140 cycles.

These numbers alone suggests that it really messes up hard with the CPU pipeline, perhaps BP (?) or speculative execution (?) or both (?) such that it will basically force the CPU to flush the whole pipeline. This is at least how I read this. I will remember this instruction as "damage control" instruction from now on.

[0] https://www.felixcloutier.com/x86/pause