Hey guys i was just wondering , when you go down to a lighter fishing line does the fish feel it as less vibration on its lateral lines. Would it just be the bass not seeing the line per say a 3 lb line to a 6lb  line?

Thinner line moves less water so there's less for the lateral line on a bass to sense.  But the difference is probably neglidgeable.  The main advantages are that there is less for the bass to see and thinner line lets the lure act more freely and naturally.