What’s the rationale for when they don’t use “this creature”?
So far, it looks like names are used for legendary creatures and "this creature" otherwise.
I thought that might be the case and looking at other Legendary’s spoiled it seems to be. Thanks!
In this case it looks like it was too use less characters in the card description, keeping the font size larger as well.
Creatures referring to themselves almost always do so by name. Usually when they say "this creature", it's because the ability was added through some other means. For example, a token might be created with an ability that says "this creature", or an equipment might grant an ability that does that.
In all cases when a card refers to itself by name, it means "this object" though so there's no difference between the two. The only time the name matters is when the card specifically refers to the name of a card, like in Approach of the Second Sun.
I don’t think this is strictly true anymore with the new Oracle language. I think the Legendary answer is correct. Skimming a Scryfall search I don’t see any Legendary’s matching “Whenever this creature enters or attacks”.
