Given that to_coinmaster has not been needed for the proxy methods of .buyer and .seller for some time and $coinmaster[ Dimemaster ] suffices for string usage, do we still need it?
Anytime you actually NEED to turn a string (from a saved map file, for example) back into a coinmaster, to_coinmaster() is your function. Anytime you're dealing with a static record, just use $coinmaster.
Basically, $coinmaster is compiled (I believe?) at runtime, while to_coinmaster is compiled on execution. That makes $coinmaster faster, but a static record unable to use a dynamic string.