I have only seen banks and consulting companies ask for GMAT or put importance on it.
For example, one time I attended Barclay's session and they said if your GMAT Score is below 700, don't even apply for job/internship. I thought it was silly but that's what the VP for Asia Pacific said.
However, I don't think you need to spend another $250 with 750.
If you ever wanted to teach GMAT, then you need 99th percentile. If you are highly competitive, then maybe too but I don't know if it matters for schools/companies whether you have 750 or 770. But then maybe I am just saying that because I have a 750 and I am very sensitive about my score