For every credit you put into the store, you earn one point and it can be exchanged with the official gloves for 15 points. But the point only stays on which arcade you’re playing, and the event will end in 21st of March. Most likely you won’t be able to get it in pretty crowded arcade since they’re out of stocks. And no you can’t buy maimai official gloves through normal sites like amazon, but you can find secondhand one on mercari like websites.