>>280229682
The answer is always the same
>time constrains (bad production organisation)
>lack of talent
Animation is a specialized craft; there are animators who jut draw special effect and if you need a good special effect animator for one episode and nobody among those are available? You'll have to make up and use anything else, either CGI or some lesser (shittier) outsourced third rater
Cars are under mecha animation and there are very few 2D mecha animators nowadays
Also
You're making an anime and something goes wrong in the production and now you're lacking time/staff due to a sudden change in the script/broadcast? You better make up in some way (read above)