Presumably he chose the different colors to make it easier to differentiate between the denominations. I would be surprised if Monopoly was the first game to use play money, so the change can probably not be attributed to the inventor.
During the Korean War soldiers were paid in military scrip :
This drives me batty with the “America” version of the game! All the money is the same shade of green. Makes sorting hell.
The houses and hotels were just chunks of wood and the earliest games had no tokens. The inventor intended people to use things they had at home like coins or thimbles or pawns from other games. Some of the early “boards” were also round and cloth to fit on a round table. sigh to be able to add one of those to my collection is a distant fantasy!
Hmmm… my first two dictionary lookups did not uncover that. Upon further investigation, two out of five dictionaries list ‘technicolor’ as a synonym for ‘brightly colored’ (though, not multi- (or many-) colored).
Mangetout’s cite was a link to Andrew Lloyd Webber’s webpage on the musical Joseph and the Amazing Technicolor Dreamcoat, first produced in 1968, and certainly appeared under that name marketed as a followup to Jesus Christ Superstar. It’s a rockopera about the biblical story of Joseph and his coat of many colors.
Indeed; there is another term in common usage (primarily in Australia, I believe) - Technicolor Yawn (meaning To Vomit), which is sort of a reference to multiple colours.
I do also believe that the dictionary references you mention probably mean or imply multicoloured, even though they only explicitly say brightly coloured (as one might describe a parrot or butterfly as brightly coloured, to mean that it carries multiple bright and possibly contrasting colours), but lets not labour this silly point any further.