I think the one (and only?) neat trick that COBOL has is supporting decimal datatypes as first-class citizens, which makes it very convenient for monetary stuff

I think the one (and only?) neat trick that COBOL has is supporting decimal datatypes as first-class citizens, which makes it very convenient for monetary stuff and other business related things where you don't want to have 0.1+0.2=0.30000000000000004 Of course (IBM) mainframes and CICS have some other tricks in their sleeves, but those are bit higher level things and probably not relevant for number crunching as such. On commodity hardware I wouldn't expect COBOL code to perform particularly well compared to e.g. C (or indeed, FORTRAN).