Yes, there is.

If you spend a lot of time standing on the pedals and not using the saddle then you will probably want the saddle to be low so that it doesn't get in your way.

If you spend a lot of time pedalling hard or fast when sitting down you are more likely to want the seatpost high so you can peddle efficiently from that position - probably high enough to almost straighten your leg at the bottom of the peddle stroke.

Trials bikes have extremely low saddles, and at the more extreme end some don't even have seatposts because they are designed for a style or riding that doesn't use a saddle.

I think 'Dropper seat posts' are a relatively well known optional feature on mountain bikes. With these you can adjust the seatpost height during a ride, which you might want to do when you transition from one type of terrain to another.

Yes, there is.

If you spend a lot of time standing on the pedals and not using the saddle then you will probably want the saddle to be low so that it doesn't get in your way.

If you spend a lot of time pedalling hard or fast when sitting down you are more likely to want the seatpost high so you can pedal efficiently from that position - probably high enough to almost straighten your leg at the bottom of the pedal stroke.

Trials bikes have extremely low saddles, and at the more extreme end some don't even have seatposts because they are designed for a style or riding that doesn't use a saddle.

I think 'Dropper seat posts' are a relatively well known optional feature on mountain bikes. With these you can adjust the seatpost height during a ride, which you might want to do when you transition from one type of terrain to another.