Square, how about scrapping magnetic strip. You can't use them any more in most of the world. #getwiththetimes
Square doesn't get to make that decision. US Banks have been issuing mag-stripe only cards, up until recently. However, if you get a new or renewal card now, it probably has an EMV chip.
Starting October, 2015, merchants in the US must be have the equipment to read an EMV card. If they don't, and a customer presents an EMV card, the merchant must accept responsibility for any fraud.
Mag stripes are still needed: pay-at-pump readers have until October, 2017, to convert. There are also interim dates for ATM upgrades.