The story really has nothing to do with Christmas- it's merely the occasion which necessitates Bingo's fateful concert. And although it was originally published as a short story on its own, it is best read in order with the rest of the tales in 'The Inimitable Jeeves', because it forms part of the larger narrative of Bingo's often disastrous- but always humorous- quest for love. In this it is much like Stephen Leacock's 'Sunshine Sketches of a Little Town': a series of humorous tales which can certainly be read individually, but fit into a larger, overarching story.
What 'The Metropolitan Touch' does do (besides entertain) is give further proof, if we needed it, about our main characters. Bingo, for example, is a well-meaning sort who genuinely longs for romance, willing to do anything- no matter how outlandish- to win the girl... aside from holding down a steady job, of course. His downfall generally has two contributing factors: his total lack of discrimination when choosing the objects of his affection, and the fact that he's a complete idiot. In any story containing Bingo, Bertie comes off looking positively intelligent by comparison. Even though Jeeves has said that Bertie is "mentally negligible," at no time does he ever approach the monumental lack of common sense displayed by Bingo. While Bertie Wooster is no genius, he always knows what's socially acceptable, and can tell when people are reacting negatively to a situation (like the concert), things which the tone-deaf Bingo is completely oblivious to.
We also see another facet of Bertie's character: his loyalty to his friends. Bertie always gets dragged into Bingo's messy love affairs, at great inconvenience to himself. Partly, this is because he's a push-over who can't firmly take a stand, so generally ends up doing all sorts of things he'd rather not. Mostly though, it's because Bingo's his friend and he genuinely worries about him. This is ultimately why he reluctantly- and frequently with great irritation-allows himself to get entangled in Bingo's affairs of the heart.
So, if you're a fan of Wodehouse, or just of witty British humour, you can't do much better than picking up 'The Inimitable Jeeves', containing 'The Metropolitan Touch' and many other delightful tales.