Since face swapping tools crop.up frequently, what is their pitch? What are the non-abusive use cases for face swapping?

Entertainment (memes). Trying out a new hairstyle matching your face.

The hairstyle thing sounds like a killer feature, but I think that it would be relatively quickly overtaken by whoever makes it easier to create 3d models of yourself at metahuman-like level.

Putting yourself or a friend in a movie scene, for example.

Lol, literally what I use it for half the time for meme reasons.

Digital marketing agencies can make website team pages look much more professional without having to go to the expense of a photo shoot

Perhaps this is a bit cheeky, but I think it'd be pretty hilarious if a company, intentionally or otherwise, used this to generate a bunch of uniform headshots that made all of the employees at a company look like they're in way better shape than they actually are.

So the model and photographer lose their job but the company bottom line is unchanged.

I use Roop (which this is a successor of) to make stablediffusion pictures of myself (e.g. for my slack avatar).

Amusement. Putting your mates in a film scene. Making silly memes. Etc.

Not everything needs a “serious” usecase.

It does where the negative use cases are very harmful. I can think of many fun projects I could pursue in my chemistry lab if only the precursors and equipment for mass producing nerve agents and high explosives were not tightly regulated.

At least that check is not hosted elsewhere and the author is clear from any defamation deriving from their programs use.