I don't see the point of that? You already get quite a lot of mana, getting more increases to a damsel would just make the progression faster, which is not an issue I care about.
If you draw a Lover and the Mystic overflows her count by one more it makes no difference and still feels bad. If you spend 2 minutes tapping the game every 20 minutes to use all the mana you are given, you still spend a lot of time on the game Mystic or not.
I guess it would help you reach the Heart shop faster? Unless the Mystic is acquired from the heart shop itself.
If it's something you get from acquiring Lovers it would lessen that issue? But I'd rather have something when I waste mana drawing a Lover than a passive chance to gain more progress when I draw a card I want progress on.
I'd prefer the dev spends their time on features that make spending mana less time-consuming and drawing Lovers less disappointing.