I have a very similar philosophy as an artist. The more time you spend on something, the better it will generally be, and the only way to increase how much time you have is to use it efficiently.
That's why I try to draw fast. The sooner I finish my roughdraft, the more time I have to deal with any problems I run into and improve on my design. If I realize I'm not happy with the direction I'm going, less time was wasted on it, and sometimes taking your time while doing too good of a job ends up hiding the problems with your initial plan until you have reached a dead end.
It's really easy to waste time without realizing it when you work at a comfortable pace, and I find that I'm able to make good art much more quickly than I believed myself capable of. (also, when it comes to art, being too much of a perfectionist can limit your creativity)
Planning and thinking ahead definitely has its place, but I find myself doing a wasteful amount of it. You've gotta know your own tendencies and capabilities and adapt your workflow accordingly. Everything has a limit on its usefulness.
TLDR: No shame in cutting corners, not all time spent is of equal value.