Yes, the default workflow on the product is that all prints go via their cloud service. For the first year or two of the X1C's existence this was the only way to print, but they later introduced lan mode.

Leading to obvious speculation as to why they have stuck themselves processing megabyte g-code streams between your desktop and the printer on the same network...

But since cloud use is optional anyone with the security/reliability/longevity concerns just don't have to use it.

Personally I don't see the cloud stuff as providing any value at all though I know people whose kids print stuff from their makerworld site via their phone app that consider it useful.

I have absolutely no insight into their operations or requirements, but when I see someone forcing traffic to their servers, I immediately think they’re looking for metadata, or training NN models on your data. NN generating 3D models is pretty valuable at the moment, and taking users data to train models without informing them is for some inexplicable reason considered ok even by many people that get foaming-at-the-mouth-mad over other privacy violations. Like I said, I’m just spitballing and have no knowledge of this operation, but it would give me pause before using it as a professional 3D artist.

Well yeah if you're not using LAN you're using WAN which means internet. But the option is there to use either one if you want, or even just put a physical SD card into the printer directly if you want, no network needed at all then, LAN or WAN.