It basically means skin . Think how pudding forms a dry skin. It isn't critical with bacon but I do like to do that step if I have time. Often it just gets patted dry then onto smoke if I am feeling lazy. There is a slight difference that I notice but if could just be in my mind .
Definitely makes a difference when smoking fish though.
Honestly homemade bacon is one of the easiest things ever. I have experimented with all kinds of homemade cure rubs but I kept coming back to the premade Hi Mountain brand buckboard bacon cure.
Hardest part is weighing the pork belly. Grams is preferred , divide it by 25 for the buckboard cure ratio. Rub it all over the pork belly , stuff in a zip bag and leave in fridge for 5-7 days. Once a day pull the bags out and mush them around the meat a bit.
If you like your bacon on the salty side you don't even have to fresh water soak. Just rinse , pat dry and onto the smoker with heavy smoke but low temp. 220-225 until it gets up to about 140-145 f. If won't take any smoke flavour after that.
Don't worry if it seems a bit harsh smokewise if you try a piece right away. It needs to sit and equalize a bit like cold smoked cheese. A few days in the fridge, but it also will do the same in freezer if you wrap it well and leave for longer.