[01HNNWZ0MV43FF]

It's not popular enough. I love Lua (except for 1-indexing) but I can't use a language if nobody else uses it

[pjmlp]

The games industry isn't nobody, that is how Lua got its fame, being a common scripting language, before Unreal and Unity became the only two engines most people know about.

[ginko]

Lua has been around for ages. I've never heard of CEL before today.

[samatman]

Lua is in the running for most-used language, second only to, possibly, JavaScript.

Few people write just Lua (although professionally speaking, that was me for several years) but many people write some Lua. It adds up.