Social distancing in the vegetable garden;)

As reach is determined by height, you wont have a very big lawn area V

Cheeky 

Is grass not useful then?

Nope. Its too needy (and weedy). Regular mowing required and you can't eat it. 

As a retired head groundsman I have to take you to task on this one veggie!  A lawn is a lot lower maintenance than a herbaceous border or even an allotment. I have a small lawn for sunbathing etc and a small wildflower meadow. My lawn isn't pristine and is kept at about 25mm which allows clover to flourish which keeps it green and the bees love it. Old habits die hard!