In most cases, 144Hz is marginally lower on the scale than a 165Hz monitor. While 144Hz is widely considered the gaming standard of today, the higher refresh rate the monitor can provide the better.
165Hz monitors provide smoother gameplay and in most cases, faster response times and less input delay. This is especially important in high-speed quick reaction games. The slower your monitor kicks out frames, the more input delay you'll have which means other games who use these monitors will have an advantage in some cases. It's a small advantage of course, but one that any pro gamer won't risk.