Even a little less pressure can help your sound. Pressure against the lips can stop parts of your embouchure from vibrating. Less pressure will allow more of the lip to vibrate, you get more signal giving you more sound with less effort. You also get better endurance, tone quality, you don't beat up your chops as much so you recover better after gigs. You also don't have to blow as hard because the lips will vibrate will much less effort, taking less air, giving you longer phrases. Your flexibility will be better as well. To achieve this you need complete development of the embouchure so it will keep the lips touching. Lips just touching will vibrate very easily, and less pressure will help the easy buzz. Pressure gets used because of a lack of embouchure development and air speed. Pressure holds the lips in the mouthpiece. Lips pressed tightly together are very inefficient, needing a lot of effort to get them to vibrate. A more relaxed inside will vibrate with little work effort. Lips just touching using the developed muscles of the embouchure to hold them that way, and flowing air will make playing much easier.