I guess this wasn't as bad as the literal skinsuits/ possession skinsuit stuff I've seen popping up in hentai somewhat recently. I don't mean to kinkshame, but man I don't get the appeal of that at all.
Anyways onto this, it was cute for what was essentially forced feminization smut I guess?
the big part of the appeal is actually moderately explicit in the work funnily enough. the bit about how searching for senpai is cover up and distancing from the kouhai's real goal of living as a normal goal is mirrored by the distancing mechanism of dubious consent forcefemme from the very stigmatized desire to live as a girl, and the even more stigmatized desire to be a normal sexual being as a girl.
the rest is the usual "this is highly stigmatized and therefore erotically charged." if you "wanted to be a girl" before puberty, and were in denial, then during puberty it can be incredibly obvious especially if you "cross"dress or think of yourself as a girl. sexual excitement that was purely dysphoric becomes much less dysphoric when "cross"dressing in the same way that just existing previously became less or not dysphoric when "cross"dressing. yet the massive stigma, and the crushing guilt and shame, and the scary weird sexual feelings, and usual kink formation kinda all kick in.
like personally my "compulsion" to "cross"dress felt very forced and external to a part of me that was very aware that a "guy" wanting to be a girl was Very Bad and Perverted and Dangerous. the fact that it just removed dysphoria prior to puberty and did the same after puberty didn't make finding "forcefemme" stuff less recognizable. it was very close to my experience of being unable to stop being trans, and having distancing mechanisms like 100% repression and denial during the day that i was "cross"dressing and thinking of myself as a girl at night. plus the burgeoning weirdness of sexual feelings only working normally when i wasn't dysphoric, depersonalized, dissociated as shit coinciding with the guilt and shame of "cross"dressing and wanting to be a woman, and the feeling that this was coming from outside myself, and my masochistic tendencies really made forcefemme genderbender really work and be painfully relatable and also make me so guilty and ashamed i could die.