I've been a PC-98 apologist for about as long as I've been in the fandom, but objectively speaking I think what you get out of the games depends on what you expect from them. HRtP is definitely the most opaque and inaccessible game in the series, but I legitimately do think it's fun to play now and again once you learn all its systems. And while I only ever 1cc'd PoDD on lunatic once, I personally think it's a superior game to PoFV. LLS has a very pleasing vibe that I still love to this day despite its occasional nightmare design with rank, and Mystic Square is more or less equal with the Windows games in my opinion. It's only SoEW that I would call a mediocre game, but even then it's a worthwhile experience to see where the series evolved from.
They certainly are not a recommended starting point for the series, but I think a playthrough of the series would be missing something without them. Plus, the music is still some of the series' best, at least in my opinion. Every era of music has lots to offer, but there's a uniqueness to PC-98's vibe that could only exist in the series' earliest years.