That isn't really comparing like for like though is it, given LightPaper is _only_ available for the Mac, is a paid app (inexpensive, yes, but not free, and the site says nothing obvious about future update policies), and not open source.
If I want to make chips, fries, wedges and jackets, the fact that a cucumber has far fewer calories and goes really well in a tuna sandwich is, while true, hardly relevant!
Lightpaper looks like a fantastic markdown editor! But the landing page makes me feel like it isn't getting much love from the developers. The copyright notice at the bottom, for instance, says 2019.
Compare that to the < 6 MiB for LightPaper, the app that I use on macOS.
Not to mention the security holes from the thousands (millions?) of Node modules an app like this probably contains.