If all you care about is cost (or if you need 4 separate beds or have two groups wanting privacy), then yes, 2 studios may be better than a 1-bedroom.
If you want a kitchen, in-room laundry, seating space away from beds, a guarantee that everyone is together, and a large tub (in many resorts), then a 1-bedroom is better.
The use cases for studios and 1-bedrooms are different enough that cost (either in points or in dollars) is just one factor to consider.