Thanks for the opinion.

My purpose is not just to save space; it'd easier to create the kind of pivot table that I envision if I could place multiple data in one cell.

For example, in the example given above, I could easily create a pivot table that counts different transaction attributes per customer. I'm not sure if I can achieve a similar feat with one pivot table if the different attributes (i.e., payment type, online/offline, referral/regular) were placed in separate columns. (You can create three pivot tables based on each attribute and combine them after the fact, but that will take time and energy.) Hence my wish for multiple data entry in a single cell.