This is an internal configurable field that traditionally had basically no impact on how fast things generate. Seems like (at least with Folia) there might be merit to adjusting this based on machine spec/config. Need to do a bit more digging.

Large enough values appear to still have no effect, however with enough CPUs it does seem to make sense to bump the defaults a bit. Adjusted in 9e447d4 to keep the default low for systems with low CPU count, but scale it enough to make a difference for anyone with a beefier machine.