It really depends on the kid in question as to whether it is beneficial or not.

Personally, for my kids, I'm not a fan. I don't have the time (or patience especially whilst extremely morning sick) to sit down with them and do it properly with them. And if it isn't being done properly, then it isn't of any benefit.
And in the case of my eldest (who is severely dyslexic) it can actually be detrimental, and she can actually 'unlearn' things she previously knew, if she spends too much time on it or is not in the proper mind frame to work. Luckily, her school and teacher are very involved in her education and understanding of these issues. As such, she still gets homework (and has a whole stack of supplementary homework), but there is not pressure on her to do it, it is completely controlled by her how much and what and when she does stuff. Nothing designed to take her over 15mins to complete. This works for her and us, the main benefit being that it keeps her interested in academic learning, rather then causing her to hate it. It doesn't really improve her grades at all, but we are all ok with that, so long as she remains eager and willing to learn at school (where they have to proper tools and resources to help her).

As a result, we don't push the homework with our son in Kindy either (and I don't place a huge importance on it at this young age either). Thankfully, the school has homework set up so that they have it over the weekend, so he will generally sit down and do it in one hit on the weekend with DH.