Sorta. Perhaps surprisingly, Numbers stations - Wikipedia are still a thing in 2025. Shorter transmissions still benefit the agency sending them and the secretive people secretly receiving them.
Oh. Well, I was thinking of spies operating in foreign lands doing their best to avoid being caught transmitting. That would definitely benefit from shorter messages.
I’m going to guess that the majority of numbers stations are now mostly dummies, meant to waste the time and effort of foreign intelligence agencies. If a spy has access to the internet, there’s all kinds of ways to secretly transmit info. OK, there’ll still be the occasional spy who doesn’t have access, but then they have to have a potentially incriminating shortwave receiver.
If we are assuming that the codes are being sent these days, then there are much more secure methods than those discussed in this thread.
It’s also not like spies are using book codes at all nowadays. There’s no good reason not to use computerized asymmetric key pairs, like everyone else.