At first, the naming change seems useless. At second thought, it might help with discovery as "draw" is very generic (end up calling it "draw io"). Third thought is why did they chose something generic again, instead of creating a unique name?

The name draw.io seems to be everywhere in the code/documentation/community/stack overflow still and even searching for "draw io" shows "Draw.io - Diagrams.net" which just adds to the confusion.

Probably either names would have been fine, but at least be consistent about it.

Afaik they only wanted to get rid of the io tld, as it is quite insecure.

What makes the .io TLD insecure?

From their blog: “ There are two major problems with .io domains:

The first is that the islands which should own the domain suffix, don’t, thanks to a wonderful piece of modern day British Imperialism. If you ever feel the need to donate to us, please give it to a more worthy cause.

Secondly, there was a security issue with the .io domain. In 2017, a researcher managed to take control of four of the seven authoritative name servers for the .io domain. We accept that mistakes can happen, strong processes limit the chances of them happening, but they still can.

However, the domain administrator made no attempt, at any time, to communicate with anyone about the issue. We’ve no evidence to suggest there is anything to be worried about, but the complete lack of communications means we have lost trust in whoever controls .io domains.”

https://www.diagrams.net/blog/move-diagrams-net