> Likely maximum 10% even.

Intel, AMD and Apple would very likely be willing to invest an insane amount of money for a 10 % performance increase. So, if this indeed increases the performance by about 10 %, I'd call it a very good idea.

Ah, I meant something entirely different: that somebody looking like a jerk because there's ugly code that is very necessary for good performance... is likely true for only 10% of the time.

I'd wager the other 90% are OSS maintainers being jerks. Occam's Razor and all that.