I do not understand why SO did change the syntax for adding links from questions and answers bodies and when adding links in comments.
To add links to the former, you use [link text]  link address
To do the same while adding a comment, you simply use [link text](link address)
I had tried many times before to use the first form, in comments, just to remind myself (I once knew this, but forgot) that the syntax is different, after finding an answer as to how to add links to comments.
I understand that the 1st form offers the possibility to reuse the link throughout the question/answer, but making the syntaxes different makes it counter-intuitive and harder to keep these things in mind.
Perhaps overall the statistic says that links are not reused much in questions and answers - and I think many would agree that the 2nd form is more intuitive, if we have to choose from the two.