If your data will fit on one SSD that is very much the way to go.
A larger SSD will have more underlying nand chips that can be accessed in parallel to improve sequential performance. Sort of an internal raid-0.
Raid-0 on hard drives does nothing, as a rule for normal desktop operations.
The benefit comes from being able to overlap accesses across two drives, and that pattern is not common unless you are processing large datasets sequentially.
Benchmarks look wonderful, but are misleading.