Earlier quoted context omitted.
Yes, it is helpful to have cell service, both in China and in the United States.
You can get by without cell phone service in the USA. On all my business trips back to the USA while living in China, I didn't have much a problem (free open wifi is pretty common, you can even use Uber pretty easily without a phone number). In China...if someone else can get you a SIM, you'll be OK, or maybe you can get one at the airport in customs (that used to be possible), though they have been cracking down on…
?? I use Google Fi which has agreements with providers in almost every country, I had data as soon as I walked off the plane in China. Alipay was almost as easy to set up, although I understand that until recently it was limited to those with a Chinese bank account.