I'm not sure about this, I may be exaggerating, but aren't all four apps you mentioned (Spotify, WhatsApp, AirBnB, Uber) built on Electron? So they'd be using SQLite in the Node portion as their storage. That's their "server side", not client side.
For that portion (the locally-run mobile backend - the middleware) I guess it would make more sense... so I see what you're saying.
[Edit: Of all 4 things - Maybe only Spotify is actually an Electron app...? Although I'm confused as to how the rest could leverage NodeJS locally]
I would consider the entirety of one of those Electron apps to be a client since their main purpose is to interface with an external server—even if a small part of them internally is itself a server.
Think of apps Spotify, WhatsApp, AirBnB, Uber, etc. Not to mention mail clients, web browsers, etc. Probably 90% of non-web clients are using SQLite.