It's going away more slowly than the telegram and the letter, but bit by bit, the check is becoming one more bygone relic of Sherlock Holmes's Victorian era. Not having the charm or personality of those other two, I doubt too many will even indulge in it as an affectation once it's gone. But this is check-writing time of year in the old Sherlockian world, renewing annual subscriptions, signing up for events, etc., and it's transition out is felt now a bit more than the rest of the year.
Since the personal check didn't come around until the 1800s, it has a definite Victorian flavor to it. Sherlock Holmes got paid with a handsome "cheque" on occasion. Professor Moriarty seems to have written plenty of checks. And Dr. Watson . . . well, there's that odd bit where Watson's checkbook was kept locked up by Sherlock Holmes.
It's been theorized that Holmes kept Watson's checkbook locked up because the good doctor had a gambling problem, but I would suspect it was for a more mundane reason -- checks in that time were probably only used to move larger sums of money, for things such as the investment option that Watson's friend Thurston had him considering. Holmes refers to the money in Watson's account as "your small capital," which probably means they were Watson's primary assets of the time -- more of a savings than a checking accounf for everyday matters.
Watson undoubtedly used cash for most of his needs, and cash will probably hang on quite a bit longer than checks -- certainly nobody got their identity stolen this holiday shopping season by paying with cash. And in Watson's time, checks were probably not as prevalent as they were in the late 1900s for the same reason they're in decline today -- they were a more costly form of transaction for those institutions processing them than other available means: cash then, debit cards and online transactions now.
Of course, the rise and fall of the check could also be due to one other factor: it's a rather tedious little thing, and while writing one's first check was, at one point in our lives, a happy symbol of becoming an adult, as the years pass, it is a chore whose absence no one will miss . . . but it will make a neat footnote the next time an annotated volume of Sherlock Holmes comes around again in forty years.