Tapping in training is important.
No one should be hesitant to tap in training. Not every exercise needs to be a struggle for victory and if you’re spending your energy on trying to win instead of trying to learn then you need to step back and reexamine your approach to training.
When your partner taps it may be because:
They feel that you have successfully applied a technique that you are working on and they want to reset to continue practicing that technique…
They feel that you are applying excessive and unsafe force and they are acting to prevent injury…
Continuing to struggle would detract from time that could be spent refining a specific skill…
and many, many more reasons…
Class is for learning. That may mean that you perform the same technique dozens of times as a single component of a sequence. If, for example, the purpose of the class was to teach a takedown then having a partner tap as soon as you begin to apply a hold following the takedown is entirely reasonable. The class (in this example) is about the takedown, not the arm bar or leg lock that comes after the take down. If you make every takedown a struggle afterwards to apply a hold then you’re taking time away from yourself and your partner to be honing the take down while you have time with the instructor to get feedback.
Even in sparring sessions, the goal isn’t always “victory.” The goal is learning and honing your skills. You should talk, briefly, with your partner about particular goals in a sparring session so that you can best help each other but those goals don’t need to include a win condition.
There is no winning or losing in the classroom. Only learning.