Can't think of any reason why Nebula creators would go for this one other than to blend in with the platform's corporate house style for the 1% of users pedantic enough to notice and... well they could have picked an existing SIL open font for that if it had been about simply minimising creators' costs
I'd understand it way more if they were a big corporate creating something very distinctive and very closed source for their marketing material...
As a visual designer, sure, it is you job. As a computer user whose ultimate goal of using a computer is something else... I am kind of an old fart, but I often find that the best content is often found in conjunction with "font-family: sans-serif".
Day to day, I use open source fonts that Butterick recommends. But once in a while, I like using just nice stuff. It's like a nice fountain pen for others.
but again, I am an old fart who is sad gopher lost.
Collectively their creator/owners will be paying thousands of dollars/month for their fonts. Something you’ve correctly assessed that a very low number of their viewers will notice or care about.
Nebula can make one upfront payment (likely less than a single months font foundry payments for their owners), and give the creators absolute certainty that the created font is free forever, no matter the viewing platform or medium.
Seems like a decent place to allocate some idle cash.