Wireless option legacy_rates '0'

Hi

What are the pros and cons of the wireless configuration option option legacy_rates '0' ?

From what I understand, it disables 802.11b rates (such as 1 and 11 Mbps) but doesn't disable 802.11g rates such as 6 Mbps.

Therefore the minimum rate becomes 6 Mbps instead of 1 Mbps, which should help for broadcasts. However I wonder if it can reduce the range or the reliability of my network?

I don't have any 802.11b only device.

Also, does the option have any effect on 5 GHz networks?

yes, if you use qca chipsets as they can transmit cck rates on 5ghz

also can the option require_mode 'g' improve performance or it has no effect if there is no 802.11b client anyways?