[tragomaskhalos]

Suspect that in the majority of cases it's a bit like people inventing their own (human) constructed language - it's an interesting intellectual exercise in its own right and allows the inventor to indulge in a bit of wish fulfilment by emphasising features that they personally value.

As in the human conlang case, it would be alarming or bizarre if the inventor genuinely expected others to start coding in their language, especially if it has no compelling features that are not found elsewhere: although Perl, C++, Rust and others came primarily from motivated individuals "scratching an itch", those langs were able to flourish because they fill(ed) an empty evolutionary niche.

What I do find peculiar is other people then piling in with all sorts of suggestions for enhancements and tweaks that imply that the particular hobby language in question does have a legit future out in the field.