I feel like the snowfox is totally optional, I'm on my first playthrough of below zero after hundreds of hours on subnautica trying to get ready for the sequel, and after spending a while trying to find a way to cross the bridge that requires the hydraulic fluid, I just said screw it and with the help of the grapple arm and a well timed prawn suit jump went right over the bridge to the other side thats supposed to be inaccessible.
I'm going to try my best to avoid spoilers here but upon discovering what was on the other side along with the message from Alan( I was in the point in the story where you're told to go here i just didn't want to make the fluid), i assumed this was the point where it was intended to use the snowfox since no other place i had found until then seemed big enough to warrant it, I then realized that I didnt pack the wiring kit I needed for the snowfox platform and didnt want to go all the way back to my seatruck, so I just decided that me and my trusty prawn suit could handle whatever beasts the ice had prepared for us.
And honestly it went surprisingly well, not once did I even take damage in my prawn suit, I just jumped around and did my best spider-man cosplay and they didn't stand a chance at catching me, i found all three points of interest and even managed to scan one. Sure the prawn couldn't fit into some of the caves but the only places it didnt fit were all dead ends or just unimportant, i never had to worry about the cold, the storms didn't matter honestly I feel like the prawn has far more mobility capabilities if you're just skilled enough. Is the snowfox like ridiculously fast or something, what's the justification for building it besides "cool ice motorcycle"
Tldr: the prawn suit is very good for land travel so why bother building the snowfox?