I think the measure is in place FOR casual root users. No doubt there will be ways to remove the check for root, but then you've installed a non-standard applic

I think the measure is in place FOR casual root users. No doubt there will be ways to remove the check for root, but then you've installed a non-standard application, and Barclays are presumably no longer liable for losses. If you were a casual root user, installed this app, and there was some back-door only accessible via rooted phones, it would be the bank's problem. Whether this is a reasonable security measure or not, I imagine it was their line of thinking.