I flew international D1 with a lap kid a few times. Like others have said, there are no skycots up front and I can’t even think of where they’d be able to install them if they wanted to.

When the child is too small for their own seat (not just physically, but also emotionally), D1 is the way to go (assuming you have the miles or the cash). It is vastly more comfortable sharing a D1 seat with an infant than a Y seat, and everyone sleeps much better.