So, full disclosure, I am cis, and exclusively attracted to men, since that is sure to influence my viewpoint on this.
I am of course referring to this: https://tvtropes.org/pmwiki/pmwiki.php/Main/EveryoneIsBi
I think that this is essentially the laziest way to do gay/bi representation. Everyone's just inexplicably bisexual. I'm sure some people are happy with that for whatever of what I am sure is long list of valid reasons. If you like games where you don't have to worry about this, I'm not arguing that you shouldn't. And I can't know how bi people feel about this at all from my experiences alone, so any bi people with an opinion on this please do share so I can further develop my own perspective on this.
Like, when I want representation, I kind of want it to reflect the real gay experience. That means the tragic bits too, including that not everyone is on the table as a potential partner. And that doesn't even mean having only one in ten or so characters being an option, I have seen VNs where there are so many gay people that it is clear that there is something in the water making everyone gay, that represent that aspect better. Something like getting the wrong signals and getting turned down by someone who can't reciprocate your feelings towards them? It's a tragic experience, but one that can be worth representing in media, because it's a real experience. But I don't know if that ever will be represented properly, queer people are already a small portion of the market, queer people looking specifically to be tragically rejected by a straight person have to be an absolute minority.
Why I say this is possibly a step backwards, is that games like Dragon Age: Origins (2009) had romance options that all had distinct sexual orientations, you had two straight and two bisexual companions you could romance. Fallout NV had no real "romance" options with companions, but did have Veronica and Arcade as distinctly lesbian/gay. And honestly, this seemed a bit more... it feels really fucking wrong to say "natural" in this context, but I will say it feels uncanny in comparison when I can put on a necklace in Skyrim and suddenly everyone I have run an errand for wants to marry me. Or that every companion in Fallout 4 will constantly forcegreet me after I max out friendship trying to get me to start their romance line.
It also just feels so much like an afterthought in comparison as far as the character writing goes. Looking at the games I mentioned, the distinctly bi and gay characters do feel like they have bi/gay energy, and that feels like it adds to their character design. I don't feel the same representation I felt with someone like Arcade Gannon in this type of setup, where there was a character who was like me (though to be fair I didn't know I was like him at the time I played -- well, I kind of did, but I was in deep denial at the time -- it's complicated), it just seems empty -- none of these characters are like me in that way.
Pathfinder: Wrath of the Righteous was pretty good about this. While many of the companions are romanceable by a player of either sex, they are pretty adequately explained as being actually bi regardless of your intervention, and I was relieved to see the gay man cleric companion was just not into my woman protagonist.
Also has a trans character whose trans status is actually relevant to a plotline, and you will only ever know that she is trans if you help her and her wife with a very personal matter, and even then you have to probe to learn what "medical treatment" the character is talking about it.
The representation, it was pretty good. The first one also had a poly couple where you could romance either or both of them, and they'd be cool with it either way. It's a fantasy game - why not get to play a unicorn?