I don't understand why you say they are the same as they are totally different concepts.
The suppliers are your providers. So the companies from which you buy your products. Actually you can only link one supplier per product.
And the locations are the places where you store your products (warehouses or physical stores or whatever). You can assign as many locations you need per product, they are hierarchical and are just informative.
The suppliers are a custom post type in WordPress and the ATUM Locations are a custom product taxonomy.
Whether you use one or another or both is up to you and will depend on your business logic.
I hope it's clear now 😉