Cranks come in 2.5mm increments for a reason.

A lot of road bikes come with 172 or 175mm cranks (for all adult sizes), which makes for easy climbing and grinding big gears and low RPMs, but it's hard for some to roll big cranks at high RPMs

There's a lot of nuance here that is difficult to articulate.

I think people who are racing track seriously (committing serious time, money, and effort) should seriously investigate and experiment with crank length. Therein may be the extra 1% or 10% that you need to take your track game to the next level.

One of the first things that people say when they ever get to do a group ride with an international road pro is, "Man...that guy carried a cadence much higher than the rest of us."...even when they were all going the same speeds in the pack.