Don't waste your breath writing long, logical answers. It comes down to this: you can use Mono/Boo/C#, get the job done and move on to something worthwhile, like going out and enjoying the sun, or you can spend the next two months reinventing the wheel in asm/COBOL/C++/[insert technology here].
C++ is worthwhile in the same ways that COBOL is: (a) million lines of legacy code to maintain; (b) a comprehensive guide on bad language design. Neither language will go away (indeed, we just hired a brilliant guy that used to maintain IBM/COBOL mainframes for a living) but language design has moved on those last decades. All new languages run in VMs and feature garbage collectors and there's a damn good reason for that. A few years for a computer science or software engineering degree will make that pretty obvious.