If you are doing streaming at above 30 Mbps then setting higher might help e.g. streaming from a local NAS, but otherwise having it set too high can affect standard web browsing activity.
So for the majority people setting it to low 30 Mbps value is fine.
Its one of those lovely - it depends on what you are doing with the wireless network settings.
It can reduce the usable range and is all about making sure that things like video streaming can work reliably at those bit rates, and really 4K does not need more than 25 Mbps, but some people might stream uncompressed material from a local NAS and so it may be worthwhile for them.