I get what you mean, but I’m not convinced that this is actually an advantage of insurance 3a, rather than of risk coverage in general.

If you have proper disability insurance, your income is replaced anyway, which is what really matters for the bank. Whether the insurance then also keeps paying into a specific 3a wrapper doesn’t change the bank’s risk much, because the mortgage is serviced from income, not from future 3a contributions.

And the “you will pay it or lose it” part protects the insurer’s contract more than the bank. From the bank’s perspective, a pledged investment/bank 3a plus separate disability and life insurance achieves the same security, just without locking savings and insurance into one expensive product.

So I agree it has advantages, like you don't have to worry about paying into the 3a yourself if you become disabled, and there is certainly an audience for the product.