When I owned 10.5 iPP I felt that, despite me almost not using it outside home and tethering not being a problem for me when using it outside, that I could do with 4G version "just in case".
However, when I ordered my M1 12.9 I went for wifi, because in reality there was no use for 5G in my iPad.
But the order fulfillment was delayed at the store where I ordered due to production delays with Apple so I just went and grabbed 5G base version that was available for immediate delivery.
Never used 5G thus far, might come in handy one day, but, the way I look at it, not worth those extra 170 euros that I paid for it.