Miket: You would be wrong. Oversteer and understeer are ways to scrub off speed; the brake is a much more controllable way to do that. Which also doesn't risk you stuffing the nose of the car into a wall (understeer), or sliding the tail of the car into the wall (oversteer).
Oversteer can be a way to get the car to change directions really quickly, but you lose quite a bit of speed when you use it that way. On pavement, it is pretty much always better to not get one end or the other of the car sliding. (Note: Gravel/dirt/snow can be different; the rally guys always seem to be sideways and it works for them!)
It can be beneficial for MPG to take a turn at a fast speed, because that means you don't have to slow for it so you don't have to regain that speed after you have slowed down. But sliding the car means losing speed, so you do have to use fuel to regain it.
BTW, the 360 you did is called many things, from a "360" to a "spin" to a "loop"; and the "starts to go one way then spins the other way when I tried to fix it" is called a "tank-slapper". They can be exciting, but are usually not so good for the car. If nothing else, you wind up having to do some cleaning of the upholstery. ("First you say it, then you do it!"
)
-soD