Personally this won’t make that much difference as it is only going to wait for system services not all services and that shouldn’t make that much difference. I would say the differences would be counted in seconds not minutes.

The reasoning for this if my memory is correct is avast needs some services to be running already if it isn’t then it has to hang about until it is available. So you would only be doing this is you were experiencing some sort of hang, which would probably result in an error of sorts. This would probably be in the Windows Event Viewer logs.

Personally I have never set this in over 11 years of using avast.