For deep sky imaging, good transparency is more important than seeing. No dew or dust in the air. The sky is darker and you see deeper. However your stars will be a tiny bit bigger, because good transparency and good seeing is very rare at the same time. You get good transparency right after a cold front.
For planetary imaging you need good seeing. When the air is so calm, no wind at all, neither high altitude, nor low altitude wind, no sudden temperature differences between the air layers so you can see very sharp tiny details on the planet/Moon. Mostly happens when anticyclone is above your area.
But when the seeing is good, it mostly means that the transparency is poor. And the opposite. When transparency is good, seeing is poor.
