I think headroom is essential for all monitor applications and not just mastering.
Traditional “reference” monitors are Auratones and Yamaha NS-10s. Some people just use computer speakers. The goal is for the mix to work musically on both the full range and the reference monitors. Typically, the vocal balance and riding the vocal level do better using reference monitors. You need to check at a variety of monitoring levels. The classic method for vocals is to slowly turn the monitors up until the first thing you hear is the vocal.