In other words, increase the polish of your initial releases by making them smaller and including fewer features. That's valuable advice.
But if I can rant for just a minute:
Do you need a completely brand new concept or paradigm or acronym to say that? No, you don't. This is mostly just playing semantic games and allowing WP Engine to subtly imply that they're better at building polished products than other companies.
How do you make something simple? You make it do less stuff. That's what "minimal" means. What does "loveable" mean? It means you're solving an actual problem -- you have a real Product. How do you build an SLC? You radically cut down on the number of features you plan to ship in an initial product, to the point where you have time to polish them in your initial release. That sounds a lot like an MVP to me.
If WP Engine just put up an article saying, "our software is always very polished and very usable, even in the first release", nobody would care. The way to make people care is to pretend that you've found a completely new paradigm for building software, when all you really mean is, "we're quite good at building MVPs that people like."
The article isn't talking about new concepts, it's just debating what other people intend when they say individual words, and I couldn't care less. It's like saying, "we don't focus on making our product 'fun', we focus on making it 'delightful'." Okay, but what does that mean beyond the fact that a business manager somewhere thought it tracked better with potential buyers?