I cannot comment on the new language, but Typescript is a huge spec. Yes, it has guardrails, but there is a lot of complexity to handle.
Something purpose built to enable embedding allows it to be used in more contexts. Maybe I want a Mog plugin for my latest video game. Embedding JS is possible, but no fun.
Right, this is probably the most compelling case for Mog. TypeScript is a beast. Everything you've mentioned here has been an obstacle for me at some point(s) or another.
I didn't mean to suggest there's no need for Mog either. I love to see developments like this. Deno is a practical solution for me today, but I see why it isn't a perfect forever-solution too.