On a few projects I've wished that there would be a built-in particle system in Photoshop. I know that you can do a lot with brushes, but it would be nice to have something completely random.
My workaround for this is to render something from After Effects. Yes it does work, but it would be much easier if we could stay in one program.
I'm not talking any intense functionality like there is in Particular, I'm just saying something that can take a layer or image and make a particle of it and have it shoot out from an emitter. That way we can get truly random effects. This may be pushing a bit, but if it could have some basic 3D functionality like in CC Particle World that would also be very handy for creating 3D starfields for example.
I am not familiar with the products you have mentioned, but I guess the feature might be useful indeed.