Can you not use it to pay for things? thats the whole reason I want to get one like an upgrade from apple pay

Unfortunately no, this is a passive tag that can only let you read data that's on the chip. The chip also had a unique ID.

Android or Apple Pay use your phone's NFC antenna to communicate. But they don't give out the same information every time.

That makes it pretty useless. You can't sign or decrypt an AES key, no display. I'm even more convinced that the bio-hacking is nothing but a badly thought out fad.

A slightly more advanced implant like those in passively powered RFID smartcard could do exactly this: provide a mechanism by which to cryptographically authenticate a transaction via a stored private key.

There are yubikeys which do this exactly already, just via a usb-key shaped device.

It would suffer from some of the same problems as biometrics - in that once set, it couldn't practically be revoked. And any failures would involve minor surgery to correct. But at least you wouldn't be leaving the secret key on every surface you touched.