It doesn't matter because lead-time is fungible. Saving 250ms in a pit gains you 250ms on an opponent who also has to brake and accelerate.

Yeah, in total there is a 20-25 seconds loss or so depending on circuit, so 2 secs aren’t too many percents of that but with the same tire strategy chances are your opponent has to pit as often too, so... (and this is venturing into the F1 strategy world with undercuts etc) And with these things evened out, seconds can matter although it’s usually no disaster even with a 4-5 secs stop unless you’re in a tight spot or with little of the race left. Races can quickly start to get ruined for each second after this though.

Where a sub-second difference matters is if the 20s pit stop is the limit to slotting in before your approaching competitor. Track position or lack of it has cost many titles. Undercut and overcut depend on precise pit timings to succeed.