It may seem overcooked… but it’s pretty legit way of doing 2D graphics and vfx. Heaps of games in the 90s made their graphics with 3D models baked to 2D textures. Donkey Kong Country, Command and Conquer, and many more.
In the case of Doom, they made clay models, photographed from multiple angles and cleaned up in an image editor.
Oh yes i mean using image frame sequences is 100% a legit way (I've even built a tool to do this, check: Sprite Builder), so you render the simulation/ animations somewhere else, then use the frames as you want. But doing it real-time is overkill, i.e. 3D particles/ assets are in 3D space, and you put sub viewports in your 2D game scenes to preview what's happening in that 3D space. It's not recommended.
