It's only possible if the governments are positive towards bitcoin and cryptocurrency. It's actually a good way to promote crypto... It's like crypto is travelling itself to promote so that a lot of people can surely see the ad.
There's a lot of ways to advertise crypto. Just like here in my country, since there's a lot of billboards you can see while travelling on the road, it's one of the best way to promote crypto. Traffic is also severe, and if they got stuck in the traffic they could see the ad... Only if someone would sponsor or willing to do it. But actually, I wish I could also see such promotion here in my country just like what you have saw op.
The government of the said country does not limiting the use of cryto, every individual are free to expose what they believe and what they support.
It is good to see that they are posting advertisement to promote crypto not only in taxi but also in the airport.
It might be the way for other countries to finally adopt and accept cryptocurrency. This might be the first step in the development of the crypto world.