Useful, yes.
Mandatory, nope...
Just purchased my first (Chrony Alpha Master).
For our long range shooting, knowing the actual MV (rather than estimating) speeds the process of getting dialed in at long range when punched into the ballistics program.
Also, even though knowing how to read pressure signs keeps us out of trouble, it's good to know if you've pretty much maxed out- even though you might not be getting the visible signs (flat primers, hard extraction). If your MV is indicating max pressure- you know you're at the end of the road.
While it's good to be able to verify max velocity, more often than not, it's not the most accurate load- in my experience. While some guys seem to get the tightest consistency at/near/beyond max, that's rarely been the case for me.