I don't think a 9mm 1911 would be considered "silly" as a carry or duty weapon. I know of several officers who switched to the P18 9mm Para Ordnance because of 1) proven 1911 system 2) 18+1 magazine capacity, and 3) 9mm works just fine if you know how to shoot. Although a single stack may not be my first choice, it is not the caliber.
I don't think it is "gaming" it in IDPA either. Enhanced Service Pistol is for single actions and the 9mm, 38 Super, and 40 S&W are the calibers allowed by the rules. Of course there will be a few 9x23, 357 Sig, and other such calibers. But 45 and 10MM are not allowed in this class.
So then you look at what is most accurate (9mm and 38 Super), easiest to load for (9mm), and most controllable in rapid fire (9mm). Easy choice for me in this class.
For IDPA, I shoot a P14-45 in CDP, P18-9mm in ESP, and Sig P226-9mm in SSP.
In IPSC, I shoot a Racer P14-38 Super in Open, the P14-45 or the P18-9mm in Limited and Limited 10, and the Sig in Production.
When in LE, I carried the P226 9mm most of time, a P220-45 for a while, and a Glock 17 or 22 only when forced to by Dept. regulations. Had my Dept. allowed single action pistols for duty carry, I assure you I would have carried the P18-9mm. My reasons are listed in the first paragraph, with special attention to #3.