Kevin: I take your point about limited resemblance of Crapshooters to St James as opposed to TUL. But in terms of music and tone, I see some links between the original Crapshooters to the earliest version of St James. Just my personal response, of course. As I've said, though I make no claims to be any good, I am not a singer, more of a musician and music communicates.

It's partly about humour.

If you listen to Fess William's Gambler's Blues (which is an earlier version of St James' Infirmary, very similar chord sequence, copyrighted by people who kept out of the copyright legal battle) it is spoken/sung by a man who, I believe, did comedy, the spoken parts by the band are comical, and there is musical humour in the arrangement.

https://www.youtube.com/watch?v=pnrT2U_pA0k

Listen to the bit after 'jazz band on my hearse'. The same joke is in Martha Henderson's Crapshooters, albeit it expressed in different music.

Gambler's Blues as done by Fess Wiliams also has the dead march at the end, the same dead march mentioned in TUL. Ditto the Copeland Crapshooters. I imagine both versions may spring from stuff being played on the circuit and people taking up an idea and running with it. Just a guess.

Just listened again to the Armstrong Savoy Ballroom Five version; you forget how well he could sing. It is very good. In the 2nd early version by Armstrong, the slower one, he giggles in a couple of places, I think he is playing a character, probably a pimp, as Harwood and others have suggested.   

Another ludicrously hot day! Staying indoors with curtains shut.