I think that helix doesn't have vim motions is a core part of its identity.

Or, rather, what's the difference betweeen "helix but with vim motions" and a bundled vim distribution?

I see Helix as a polished-out-of-the-box editor with kakoune-style motion, LSP, and tree-sitter (which supports enhanced motion). -- I think each of these things is a nice improvement over what came before; even if vim motions have long staying power.