Will help to secure your wallet.
No, it won't. You're under the same misunderstanding that Atlas' Woolong device is. RFID won't work for Bitcoin in the same way that it works for credit cards and so on, because Bitcoin is irreversible.
I can use RFID and a highly directional antenna and snarf blink/paypass supported cards' details, then use those details to spend the money. The owner of the card can then file a complaint and have the transactions reversed, etc etc etc.
With Bitcoin, if they're gone, they're gone.
So a RFID for Bitcoin is dumb as hell, unless it has a few redeeming qualities. First of all, it needs to be more than just a dumb device that gives out the private key when asked. Ideally, it needs to be more like the smartcard type model - where you zap a transaction over to it, and it signs the transaction with the private key and sends it back, where the merchant can then upload it to the Bitcoin network. If you hand over the private keys and expect the merchant to be honest, well let's just say there's all manner of ways that it could go wrong.
Second, obviously you don't just want it signing over Bitcoins every time any merchant device asks it to. While in crypto-geek fantasy it's worthy of masturbation to think you can just have a GLaDOS-esque voice saying "please pay 0.25 coins for your meal" before you rub your wrist up near a scanner on a wall, it's a bad idea. Again, I've got a highly directional antenna and less than $200 in hardware and I'm going to rob you blind, from a distance. So you at least want it to only sign a transaction when you undertake a deliberate and hard-to-do-by-accident gesture.
Finally, and this was my same criticism for the idea of smartcards for Bitcoin: you need some form of acknowledgement of the amount of the transaction built in, and it needs to come from somewhere you can trust. Apparently you can get smartcards that have screens on them, which solves this dilemma nicely. You can't have the merchant's device's screen read out the transaction, because you can't trust it. What if I work as a janitor at a merchant, and I hack their Woolong devices or RFID scanners to transfer all coins to me from any account that they interact with? It reports the correct amount and the correct address on screen, but it signs over the balance of your private key to me instead. You can come back and yell and scream at the merchant, but that won't get your coins back. No, the only readout you can trust is the one that you control.
An RFID chip for Bitcoin is worse for security than tattooing it on your inner thigh, because at least that way it couldn't be stolen at a distance. In all other respects, the security is about on par with carrying around a copy of your private key and giving it to everyone you want to pay.
