It means they were hand finished, in other words they were laced up by the big lacing machine that takes the tedium out of lacing (and does it way fast) but the truing, tensioning and stress relieving was done by hand.
Does it create a more stronger, durable wheel? Yes, it can, depending on how good the wheel builder is.
One thing is that the wheel is checked throughout the truing process and doesn't leave the jig until the wheel builder is satisfied with it. With factory built wheels, a lot of them come off the machine and into a box with the expectation that it's right.
If you build your own wheels you know what it takes to make a durable wheel and you like to think that human hands can do a better job than the machine.
Grumps