One of the nice things about adjustable bass is sometimes you think you want more so you just dial more in. Then in a few days you realize you had it right before lol. Bass has a profound effect on musical enjoyment and enjoyment for the system as a whole. It is the most important thing to get right. sometimes I have trouble telling which speaker has better mids or highs as they are often just different not better but I can tell in just a few seconds which system has better bass.
the nice thing about a high pass is you can play with the crossover point. you can technically put it anywhere you want (30-120db) and really let’s you dial in the sound power/hand off to the main speakers. Without one you have to come in real low as to not cause a hump and corresponding dip in the overlap between the sub and mains.