I tried deadlifting with bare feet a few weeks ago, and it was awesome!
It first occurred to me months ago, but I kind of wrote it off because it seemed like cheating since it would reduce my range of motion.
By taking away the height of my shoes (I wear pretty thick shoes), it reduces the starting bend of my knees and hips. It also reduces the distance travelled to get to the upright position.
Think of it like doing deadlifts with the bar/plates starting on blocks. It may not be obvious at first, but removing the shoe height is the same thing (just with really short blocks).
So, technically speaking, deadlifting barefoot IS easier because you are LITERALLY doing less work with the same weight (Work = Force x Distance Travelled).
But even so, I now love deadlifting barefoot for the following reasons:
Engages the glutes and hamstrings better
Reduces stress on my knees
Reduces the starting bend of my knees
Reduces stress on my lower back
Reduces the starting bend of my hips
Reduces tendency to lean forward during deadlifts
Helps shift weight back, which is where you want it
A lot of those items sound like it's just making it easier, but even so it totally hammered my glutes and hamstrings way better than it had with my shoes on! And really, isn't that what deadlifts are mostly meant to hit anyway?
And long term, anything that reduces wear and tear on my lower back and knees, while still stressing my muscles, is going to help me keep working out and doing other things I enjoy.
These days, I only deadlift with a trap/hex bar (or hoop bar as I call it) due to lower back issues. However, what I wrote should apply to barbell deadlifts as well.