Playing note in Treble line by left hand, why?

[pi_a_no]

I'm new to this forum and piano too so I'm confusing of playing it. I have a sheet music ( sample page from order site ) with lines like that :



Yep I'm a newbie so I thought the two Db on the treble line would be played just by the thumb finger on my right hand only :



But as I saw on YouTube, the guy uploaded the video played the first Db by his thumb on right hand, and the second one by the thumb on the left hand. Here is the video :

And I realized that this method could help lessen the gap of moving the left hand between far notes. So can anybody tell me what is the name of this method, or any related information about it ( e.g : why and when do so, how to apply.... ) please? Many thanks

[tsveti]

Hi there, I'm also new to this forum, but not to the piano  No one answered your question, so... You can play the D flat with both hands. It's important that you feel comfortable and it sounds right (melody, harmony, etc.)

[pi_a_no]

Hi there, I'm also new to this forum, but not to the piano  No one answered your question, so... You can play the D flat with both hands. It's important that you feel comfortable and it sounds right (melody, harmony, etc.)

As I'm learning to play the piano and in music theory books I read they don't mention this way of playing so I thought that it could be some sort of advanced techniques and I'm really curious of in which case I should apply this. Anyway, thanks for your answer.