I am tall enough that it has never been an issue for me. I think the last time I used a screen though was 2e.Personally, I find sitting down behind the DM Screen blocks my view of the battle mat. Standing up gives me a better angle to see everything unfolding on the table.
I still have a screen for keeping my secrets...mostly just dice rolls that the players can't see because plot reasons. But that's it - I barely use it and mostly like having it out because it's a beautiful hand-carved bespoke work of art that my spouse had made for me. It's more tradition than necessity.I am tall enough that it has never been an issue for me. I think the last time I used a screen though was 2e.