What’s your thoughts on supermarket loyalty cards actually being a saving?

The BBC has just released an article to state that the watchdog found that loyalty cards provide genuine savings. However many people are not convinced.

https://www.bbc.co.uk/news/articles/cew2ejj7lkvo

What are your thoughts? I know I’m not convinced after seeing at Sainsbury’s a bottle of whiskey being sold at £50 with nectar at £25 when usual price anywhere else is £25.