A lawn is definitely NOT useless

You can let your friends roam free there!

You can mow it with your electric lawn mower, and feed it to the goats or chickens.

You can let it grow a foot long and then cut it with your cordless electric hedge trimmer.

You can plant enough fruit trees on it, that the grass doesn't really need that much maintenance.

You can move a rabbit or chicken tractor to a different section every day.

You can break it into small paddocks, and let sheep take care of it.

You can host a party there, and you don't have to clean up every little spill.

You can take your girlfriend there at night, and put the moves on her.☺

You can admire when it turns sunshine yellow in early spring and go pick lots of salads, and blooms to make dandelion wine.