It is more expensive than wood moulding but if it doesn't look good
(gaps, etc.) or is harder to work work than advertised, etc. I would
rather use the traditional approach.

I know for a fact that putting up chair railing is dirt easy so a "labor
saving" alternative is a non-starter.

The real test of a "new" technique is how it works when your ceiling isn't
flat. Check the instructions and handouts and see how that is addressed.