Don't think you're missing much luv.
Chucking out pan or bucket of water is a bit of work, but not much really IMHO. Suppose if one were doing several loads in succession it would be a bit of bother, but nothing that can't be endured I shouldn't wonder.
Problem with a pump is you don't know if it will be able to handle what could be great amounts of water gushing out at once. Washing machines of course will slow down spinning to prevent choking pump, you'd probably have to rig up something that allowed pump to continue even while machine isn't spinning (assuming you stopped things to let water in sump get clear).
Gravity drain shines in that respect in that there isn't a pump to worry about, so water drains fast as opening will allow. One rarely sees drain pumps on industrial or commercial washers (though many can be ordered with), for that reason. Valve opens, and machine dumps water.
My Hoover twin tub spin drier has a pump and one has to watch things for froth or water build up. It doesn't like it...