Standard bathroom vanities were made at 32" years ago when many homes typically were 2/1's with a shared bathroom. That means parents and children would be using the same vanity. To accomodate children, vanities were lowered to 32" which is standard height. Now that many homes have multiple bathrooms and even a dedicated bathroom for each room in the house, Comfort Height is the new norm. Comfort height vanities are 36" but this height can vary +/- a few inches either way. There is no downside to upgrading to a comfort height vanity. In fact, it's preferred in most cases. It reduces stooping and strain on the lower back.

Here is my research on both types. You can read here for further detail.