A few possible responses:
1. Stage magicians aren't limited by mana or spells per day.
1a. Stage magicians do not risk paradox, drain, insanity, or warp perils while working their trade. Real magic is far more dangerous than mere card tricks.
2. Not everyone can afford a magician to do tricks for them. A powerful noble might have them perform for dinner parties or feasts, but peasants and other rabble could settle for simple sleight-of-hand tricks.
3. Magic-users tend to have huge egos and will not normally stoop to such lows. They are no mere conjurers of cheap tricks! As such there are very few magic-user performers, but they are in demand due to their rarity and spectacle.
4. Bards, if they exist and can use magic in your setting, could fill this niche.