You can actually have multi directional, assymetric and directional, so actually 3 choices and combinations within these.
Multi directional is the tyre of choice for the cheap low performance runabout. Compromised because it can work either way, but generally cheaper as 1 tyre fits all 4 corners either way around.
The directional, obviously only run one way, but should be better than multi directional, as say thread is designed to clear water correctly, but lack the benefits of assymetric.
Ideally I'd want assymetric for performance, where say the inner part is a different tread pattern say to clear water and outer part another pattern to say assist high speed dry cornering when loaded up.
...and possibly the holy grail unidirectional and assymetric for best performance, but of course they can only be mounted on one side, and have an inner and outside so you need lefts and rights.