Indeed, for many years now there have been shops dedicated to selling nothing but cards.
My uncle passed away recently, and in addition to Skype calls to my family in the UK we naturally immediately went looking for a card to send our condolences to my mother. I say we, but it was actually my wife who did it. Sending cards is one of the (few) British customs she has adopted living in her homeland married to a Britalan. It's certainly not a customary thing here compared to the UK, where we send cards at every opportunity - congratulatory cards for birthdays, weddings, anniversaries, births, passing exams and so on, season's greetings cards for Christmas and other holidays, “Get well soon!” cards for illness, condolence cards for bereavements, “Thinking of you” and “I love you” cards, not to mention Valentine's Day cards, a reason for either joy or panic, depending on the sender, in my country of birth.
Given the relative difficulty of finding a suitable card here - or in my immediate neighbourhood, at least - I started thinking about how much the British economy makes from the sale and sending of cards: it certainly gives postal workers (for postman/woman is no longer the correct nomenclature) much more to do than in other countries. In fact, a quick shufty at the Greeting Card Association website (yes, there is one) reveals that “in 2015 the UK public spent more on greeting cards than ever before - taking the market value up to £1.7 billion”. Evidence of this statistic can be found at any British newsagent's or supermarket, where it's not uncommon to find whole walls of greetings cards arranged into categories, and by age in the case of birthday cards. Indeed, for many years now there have been shops dedicated to selling nothing but cards. This will take a Catalan visitor to the UK by surprise, given that, as already implied above, if you look to buy a card here the selection will be very limited to say the least.
A related UK custom is that of sending holiday postcards, from destinations as close as Blackpool to as far-flung as Timbuktu. This is something that is not unknown in my adopted country, although British holidaymakers are surely the world leaders in scribbling what is to all intents and purposes a public message on the back of a card and sending it to friends and family across countries and continents.
Of course, you'd have thought that the Internet and advent of online cards, so easy to select from the comfort of your own laptop and send to an email address, and often free of charge, would have obliterated the UK card market. Not so. Even though there are websites out there making money from providing this online service, the very fact that sending a card is such a personal act has allowed the tradition of sending physical cards to remain strong in the face of such tough competition. It is that personal factor that really touches people when they receive a card , perhaps representing a compensatory factor for the otherwise less expressive nature of my compatriots.