Good question.
There are many reasons and some people have different opinions. Personally, I usually prefer Bedrock since the Friends system makes it easier to play with others. Another reason is generally because I’m more used to it. More specifically, the graphics look a little better and the render distance can go a lot higher (I play on a large computer so it doesn’t crash, but I did originally play on my iPad).
Overall, Bedrock is the first edition I played on, so I have an attachment to it. Java’s great - though I wouldn’t switch to either version completely.