I definitely support this idea, particularly now that Templates has become such a great feature.
I have a template that I use as a vehicle log book for my camper van. I record the mileage at the start and end of each day's trip and it suddenly struck me that if I put this part into a table then it could calculate the daily mileage. Alas no - but I so wish that it would!
I don't want a mini-Excel, just something that will add, subtract, multiply and divide numeric data in cells.