That's not really churning.

The purpose of churning is to garnish as many points/miles as possible. Cancelling the MP just to apply again immediately doesn't count. Churning is selecting a group of cards to apply for, based on your needs and the offers available, on a regular basis. Some do it once a quarter. Others once or twice a year. Some super-churners do it more frequently.

You may discover that Chase is unwilling to give you a bonus on a new MP card right after cancelling the old one if you're re-applying for the same card.

As far as advantages/disadvantages - if you close the card without transferring the limit, you lose that chunk of your overall credit limit. If you carry a balance, your utilization % will increase and your score may decrease. Closing the card does not, in and of itself, lower your score. It's the loss of credit and commensurate rise in utilization that does.