3-4 years back, when mobile phone plans had limited Data (3-4GB per month), getting a cellular ipad was pretty resonable if you are surfing the internet with the ipad because your mobile plan didnt have enough data to tether.
if you would recalled, it was a common thing that telco will issue a 1 GB SIM card when you register for a fibre broadband plan, which you can use the with the cellular ipad.
fast forward now, mobile plans have WAY higher data compared to in the past. just to take my mobile plan as an example, i have 40GB + free weekend data. i can tether with my ipad and watch youtube on the go without bursting my data. the 1 GB SIM card issued with the Fibre plan is also becoming obsolete, or at best you are limited to 1 GB data.
in my humble opinion, to spend the extra on cellular ipad is not justified now.
you may spend the difference between a cellular and non-cellular ipad on AC+, the apple pencil, or on a good ipad case.