Hmm… The games are indeed wildly different, and there are some subtle story changes (mostly to fix retcons with R, but D gets a little more to do).
But regardless of if you think playing the same story on both hardware is worth it, the Switch game has 'Another Code: R' bundled in, which makes it a MUCH fuller experience than the DS title.
(That said, I do think all of CiNG's DS games (Hotel Dusk, Last Window, Again: Eye of Providence, and Trace Memory) are all worth playing at least once to experience the unprecedented creativity in puzzle design. Though I will admit that Again took a couple of chapters before it grew on me.)
Normally I'd agree with you, but Another Code: R interprets the Hotel Dusk/Last Window split screen gimmick quite well, and they used it in the Switch game as well.