The 70mph interstates are generally a bit scary because going 75-80 to keep up with traffic just feels too fast and I can feel how much harder it is to control my vehicle compared to going less than 70, plus the engine works noticably harder against the wind to maintain speed.
This very much depends on your vehicle.
I have found my Fold most useful for work stuff. I can view and edit word and excel documents with plenty of space to see everything. I can do it anywhere when I have some free moments without lugging around another device. For casual stuff like Lemmy and web surfing it’s just really nice to read more with less scrolling.