Originally Posted by
Connman
I ride a gravel bike on the highways an understood that clipping in would allow to not only push down but to pull up while pedaling.
People don't really do this with any sort of force (except, maybe, rarely). Forceful pulling up might not be very good to do regularly biomechanically.
One of the advantages of clipless is making a higher cadence easier. One way of being able to get a high cadence is to "unweight" (lift) the non-power leg (this is a little like pulling up but there isn't much force). The unweighting is easy to do (with some practice) and it might be a tiny bit more efficient (because you aren't using the power leg to lift the other leg).
Originally Posted by
Connman
How much on average would " being clipped in " improve the ride and the time?
There aren't really ways to buy significant speed (as long as your bicycle is decent). The biggest way to increase speed is generally free: riding in the drops. Anything else is going have a much, much smaller increase in speed.