It is better late than never

Well there are two things here as you have mentioned. One is "it is not good to be late" and the other one is "it is better to be late than never." I believe that the last statement should never be an excuse to being late, especially when a person has an important appointment and the other person should not be kept waiting. It would be an opportunity missed if someone would always be late. The other statement, "it is better late than never" is more used if we're referring to life decisions. For example, we say it's never too late to have an education, or it's not yet the time to give up on love.