There are only two reasons to improve your pronunciation:
1) It affects your communication. Not everyone easily understands you, and this happens too often. You don’t like it.
2) You know your pronunciation has a lot of errors, and you are motivated to improve it even though everyone always easily understands what you say. (Maybe, you want to “reduce your accent” for some reason.)
If you communicate well, you’re understood, and you’re okay with incorrect pronunciation, then there’s no need to do anything. Your English pronunciation does have to be correct for your English communication to be effective.
Incorrect pronunciation develops at the beginning in classrooms, outside of classrooms, or in situations that people are self-taught – or the combination. You can make it better if you want to, but you don’t have to.
Only you know whether it’s worth the energy, effort, and time to do so. Maybe, you want to improve your pronunciation, and maybe, you don’t want to improve pronunciation. It’s up to you. There are only two reasons to make your pronunciation better.
Whatever you decide to do, it takes some time and effort.
By the way, speaking too fast might cause people to not understand you. Maybe, you just have to slow down.