Although human behaviour is always proving to be unpredictable especially in cases like this, a person in it as a recipient of rewards can potentially gain long standing interest in Bitcoin which is also good for it.
However if people hold Bitcoin as a result of a reward system, and never learn to hold or use Bitcoin outside these incentive institutions can lead to an increase in adoption, but ultimately limit financial sovereignty. Is Bitcoin being accessible without being more independent?
It's just like when we offer Bitcoin as gifts to friends and loved ones, and we don't bother to know what they use it to do afterwards.
The truth is that a good majority of the recipient will not waste time to seel that Bitcoin and convert it into fiat money which they can spend. They win for once think of the value of what they are holding but consider it as a gift.
Someone who purchased it on there own, would first of all know that he is going for a long term investment and not just some random Bitcoin purchase. He already knows for a fact the value of what he is holding in his wallet so he won't just rush to sell them off.
It might be a good initiative but it depends on the person who receives it as a cash back.