With regard to Gold being too bulky and heavy to be practical. Check out one ounce of Gold weighed against its value in Australian dollars. Note also the difference in bulk. I took the photos a few years ago when Gold was quoted at around 1,600 Au$s.
On the left is the dollar amount in the largest notes possible and on the right in the commonly used denominations (no $100 bills)
It is not very relevant, as Gold is rarely used in marketplace transactions. The role of cash is reserved for silver.
Both Gold and silver will circulate digitally of course, but there will always be the need for cash. I was still using silver coins in the 1960s and I don’t recall them feeling heavy in my pocket.