Short answer: Yes! It is the same MCU with the same specs.
Longer answer: That depends on what you want to do. If you, as you seem to hint when you want to buy a Field, want more buttons, connections, a screen etc, then it is obviously not the same. But you can start with a Pod and add hardware and end up with something like a Field.
I don’t know if this answers your question, but I think it is a good idea to start with something cheaper (I’ve only bought Seeds, because I cannot afford anything else), and try out your ideas. If you like it, and have fun and make things you can use, go for the Fields (although I personally think it is a lot of money that you can spend better on building something that you create more from scratch).
My five cents!