the thing about gold in tabletop games, is that there is an underlying assumption that you are storing the gold somewhere not on your person when its in vast amounts... nobody is carrying aroudn 20,000 GP on there person.
We just dont show them fetching the gold and such.
I have never played in a 5e game where this is assumed. At 6.7 grams a coin (rough weight of real life gold doubloons), 20,000 would have weighed nearly 300 pounds.
Where are you stashing that? Where are you storing it? Why are there safes and coin hoards? If everyone has some mysterious, abstract coin storage space, there is no need for banks, there wont be chests with coins in them, you can never pick pockets and find money...
I have never been in a game where it was just assumed you had it stashed "somewhere'. No DM I know (myself included) would shrug and say ok cool np. No... you need to say where it is. You need to indicate how much you are carrying on you.
If you get mugged or attacked and fail to defend yourself, that coin could be taken from you. There is certainly the possibility of a portable hole filled with riches, or a wealthy enough organization building an extra-dimensional space to stash your riches, accessible only by a device that opens a poral to the space... things like that. But those circumstances are always defined. Ambiguous, abstract "an assumed place to store it" subtracts from the game, and creates enormous exploits.
