<human>: Can you provide a brief overview of the text?

A year ago I took advantage of a balance transfer to get the intro 0% to try to get out of credit card debt a little faster. Still, I was intrigued with the "first $1000 you spend you get 25000 miles" offer. I signed up for square (credit card processing app) and ran the card about 10 times over a few days only to pay back it immediately back once the money came into my checking. Cost me 0 interest and only 2.9 percent processing fee to square. I ended up getting the free flights.

So my question is (after I get out of debt of course) is there really any big disadvantages to signing up for a credit card from a different company when I need to travel. Get the points, use the airfare and than cancelling the card? Obviously I will need to be careful with paying it back immediately. I take a vacation about once a year so would this create any red flags if I don't have any plans on buying another house or car any time soon?
<bot>: Signing up for a credit card once a year to take advantage of travel rewards, than cancelling it. Am I going to do serious harm to my credit if I do it correctly?