Can someone explain why it's not good strategy to enter the luxury tax before having a very good team already in place?

I've heard little things here and there that suggest that if a "bad" team enters the luxury tax, they are not only wasting their money on a bad team, but they are actually stuck/unable to improve their team going forward.

I understand that teams lose their rights to various exceptions when they enter the luxury tax, but what are these specifically? For instance, when is a team no longer allowed to use the MLE, the mini-MLE, and so forth? Also, what does a team in the tax miss out on in future seasons/offseasons?

With respect to the Warriors, I know Lacob and co. have said they would be willing to spend the money necessary to put a winning product on the court, but I think myself and many others would benefit from a knowledgeable person spelling out why it's important to wait to go into the tax. (I really want to support the new regime's decisions, but I don't quite understand the rules controlling them.)

Thanks!