Agreed. Once this comes to Canada, it'll kill Interac Email Money transfers (of which my plan only allows two free per month, and is not nearly this simple).
I think OP meant the opposite. This is cool, but the incumbents in Canada have already done it, and it's more trustworthy (it happens on your bank's website) and 'good enough'. Even if the tech-savvy switch to Square, the average bank-user will prefer to use INTERAC. At best this could pressure banks into giving away more free INTERAC transfers with their paid accounts.