Many retail locations (such as grocery stores) still accept cheques. What's the turnaround on those? Seems seconds for normal transactions, and days for worst-case scenario isn't so bad, or at least I thought
but let's compare cheques anyway. consider what it takes to send an etransfer to a new recipient. you open your phone, then your banking app, then you enter a phone number or email address and set a password for it, then you can initiate a payment, type in the amount, double check it, hit send. THEN the seconds/minutes delay kicks in.
if you already have the business saved in your address book then it might be comparable with writing out a cheque, but I'd be willing to bet in the average case, etransfer is going to be a slower and more error prone.