What is the point of bleeds?
Bleeds do less damage but are easier to stack and sustain a stack of, making them valuable as a source of sustained pressure for condition focused builds.
Case and point, there are sigils that proc bleeds that can be put on any weapon to let them keep up a constant supply of bleed stacks on the target. There aren’t any sigils that inflict constant burning on the target.
Bleeds are for sustain while burns are for burst. Some builds might use these conditions differently, but that’s generally how it is.