If Sky or EE decides to increase my bill payments and I’m not home to read the letter or email I won’t get that money back. If someone uses my PayPal account (tethered to my bank account via DD), I’m going to have a battle on my hands getting that money back. What’s ‘secure’ is subjective.
I feel that having full control over the amount and date of payment is way more secure than a guarantee of a refund in ‘error’. Let’s not split hairs 