Training Milestone!

Yesterday I had a really good run. I finally managed to crack 10 km. It took wayyyy longer than it would have 2 years ago, but I still finished without feeling completely destroyed.
I didn't actually intended to run 10 km when I packed my bag yesterday. I grabbed my VFF sprints and some toe socks and decided to see if wearing those made a difference with my knees. I picked a section of trail I've run many times so I would know how far I had gone without constantly checking my phone. I started off slow, but was happily surprised that my knees didn't twinge a bit. Keeping my stride very short I plodded along, dodging sharp rocks and roots and it rained lightly overhead. I was happy for the canopy of trees so I could avoid getting soaked. I checked my phone and saw I had covered 3.3km. So far so good I thought so I figured I would keep going until I was doing more walking than running. The next thing I knew my phone read 5.1km. Sweet! I turned around and headed back the way I came. My quads and hamstrings felt a bit tight around the 8km mark but still, no knee twinges or shots of pain. In fact, the body part that hurt the worst was the bottom of my feet. It's been a long time since I've worn my VFFs and my tough feet pads have clearly softened up.
So am I on to something with this VFF thing? I don't know but yesterday's run has me thinking maybe wearing those might be the safest alternative for my own knees.
I had switched back to running shoes a couple of years ago when I got really into trail running. The trails around my area, the really fun trails that is, require a sturdy, padded shoe. The rocks can be huge and often the trail bed is clay, which in wet weather, can make your VFFs ice skates. However, I'm not typically running those trails nowadays. Nowadays the trails I travel are pretty tame, with crushed gravel and gentle slopes. That doesn't mean I still don't hit the fun trails every now and again, but the length is usually 1-2kms, not 10 or 20. So I guess there's no harm in switching to VFFs for a bit of training. Wearing them made my calves and feet stronger than they've ever been and recovering from runs was exceptionally fast. Hopefully my previous experience with them will repeat itself.