atan2 parent
Writing that programmers that use Euler instead of RK4 are "bloddy idiots" might work well to get some laughs in a blog post when the author is trying to stress how RK4 is more accurate and stable than the alternative, but there are cases where real-time applications (especially on older machines and older consoles) could not afford the overhead of RK4 and Euler was gave good-enough for what they needed.
Forward Euler is very terrible and can give you wildly wrong answers after just a few steps. If you think higher Runge-Kutta and fancy methods are too complex/expensive you do have cheap and stable options, like implicit euler or leapfrog. It's very likely that your numeric integrator is going to be a hot part of your game loop, it's worth doing ten minutes of research, IMHO.
> like implicit euler or leapfrog
Leapfrog is so easy to implement, as well. It might require a smaller timestep than some fancy techniques but it is very cheap per timestep. And given that it is accurate enough for statistical Physics simulations, so about 2 orders of magnitude more accurate than it needs to be for a game.