I realised something after Despacito,
To understand my point of view you have to know that i did quiet some research for its success.

Remember Gangnam Style, the song that took over world few years back.
Lets compare them both.
1) Both are non-english songs
2) Both are in languages that have majority of speakers in world
3) Chinese language can be understood by 1.2 Billion people 
4) Spanish is not even half 437 Million

Now i gave it a thought, Gangnam style should have a lot more view than Despacito but the fact of you tube being banned in china has a major role in this.

Besides there are two types of people in the world.
1st who read about Despacitio/Gangnam style beuing a hit, they just logged on you tube heard it and said nice. Thats it
2nd are curious, they heard it and felt good listing to it, so they went on to google and translated words of spanish to get a better understanding
they understod the lyrics and watch the song for full enjoyment.