Business use I get, sure, you need to check mail frequently, and the cost is tax deductible. The directions thing, though, I don’t get; before satnav people got around fine. I’ve driven/biked in four countries (I haven’t lived in the UK for years) and get around, even if I have to show people the address in their language. Also people have internet-enabled, expensive plans when they’re not used for business - why? Your $50-70/month could be put to so many better uses.
I got around before GPS navigation as well. But it is so much easier now than trying to map out a route on a spiral-bound map book - or if one is driving far, several spiral bound map books. And let’s not even think of getting the folding maps ever folded back right. Now I get point-to-point, turn-by-turn directions which take into account re-routings and traffic on a live basis. I love the 21st century.
Your $70/month could be put to better uses. Doesn’t mean someone else values their $70 differently.
(P.S. Business is more than just email use - a lot more.)