Apple Watch Cellular

Please read the following, which will help you understand what an Apple Watch connected to Cellular and one that is not can and cannot do

https://support.apple.com/en-us/HT205547

Make sure you read the footnotes

There is no requirement you activate cellular service no.

It will work normally without cellular except when out of range of the paired iPhone or Wifi, wherein it will not be able to send or receive messages or calls.

If you never plan on activating the cellular portion, then the less expensive GPS only model may be a better choice. Unless you want the Stainless Steel version which is only available on the GPS+Cellular models.

You do not have to activate the Cellular feature, and the watch will function fine.