Track the value of money, not the types of coinage

If money in D&D has a gold standard, then instead of tracking the number of gp you're carrying, the number of sp, the number of cp, etc., you just track the value of gp you have instead. Example, 1 cp = 0.01 gp, 1 sp = 0.1 gp, 1 ep = 0.5 gp, and 1 pp = 10 gp (all values based on 5e PHB). So 5 cp = .05 gp and 9 sp = .9 gp. Therefore, if I had 5 gp, 9 sp, and 5 cp, why not just write down 5.95 gp? If the cost of most goods and services are based on GP, then no depth of gameplay is lost. 

Pros:

• Players are already programmed to track only one value for their money by video games, so they don't have to learn anything new.
• Reading that I have 5.95 gp is faster and simpler to understand and to communicate than reading that I have 5 gp, 9 sp, and 5 cp.
• Save time on conversions.
• Simplify your character sheet. Get rid of useless coins like ep, the fifty-cent piece of D&D, and cp, the penny of D&D.
• Players can get good at math if they suck.

Cons:

• Loss of flavor for people who value it. Note that a PC can be assumed to be carrying different coins.
• Probably not compatible with VTT or digital applications.