The four words are Most Advanced Yet Acceptable. It’s why things used to come with the label “New and Improved”. It’s why Spotify creates playlists with songs you know and songs you don’t. It describes what keeps you coming back to old restaurants (today’s specials). As this piece states:
…to sell something surprising, make it familiar; and to sell something familiar, make it surprising.
That’s really it: people want novelty within their comfort zone. If want to influence people to do Something, that’s how you need to describe the Something.
I recommend you read the entire piece: The Four-Letter Code to Selling Just About Anything. It’s fascinating.