Probably because the SEs were far more forgiving in my inexperienced hands 60-plus years ago, I used those first. I was only aware of electric shavers, Gillette DEs, and Gem SEs until I got to college. then, I bought a couple of Injectors, and IMO, it was like cheating to get such good shaves with so little effort!Except for injectors, I have not found SE to be better than DE and often worse and harsher. I think for those who need more aggressive shavers it may deliver something "vaguely" (waving hands here) akin to a straight. I keep a collection of SEs because I find them attractive, but haven't found a single one that I would prefer to my three or four best DE razors. And I find the lack of blade choices annoying and uninspiring.
I can get a great shave with a DE, Injector, and SE. It is far easier to do so using the two kinds of SE, and definitely easiest of all with the Injectors.