In all honesty, the 2 drive option stems from a couple simple things. Initially SSDs were tiny, so the option was required. Also, older SSDs didn't take kindly to excessive writes (also a concern with size); for a bigger drive, you are not constantly writing to the same space all of the time.
From a practical perspective, 1TB is sufficient for size, so that both of the above concerns are not as applicable as they once were. One thing to consider is that SSDs have higher risk to catastrophically belly-up, so be sure to do a regular backup routine regardless of choice.
Even an OS SSD sees the "excessive" writes on certain areas but they still survive, resolve bad blocks, and continue to run. I have a very old 240GB Patriot Wildfire (c. 2011) that had firmware/driver issues that I resolved with fruity workarounds... but I still haven't killed it (yet).