I’ve read this setting is important for 10/25 Gbps. But I have a strange case with a 1 Gbps link between CRS328-4C-20S-4S+RM (one of 1G SFP ports) and Netpower Lite 7R (10G port with 1G module), about 300m of single mode fiber with cheap 1550/1310 1G SFP WDM modules, suddenly started to have high packet loss (RX FCS errors on the Netpower Lite side, and after each error the switch renewing its DHCP lease). Optical power levels on both sides still good. Changed the rate select on the CRS from high to low, and packet loss stopped - is this just a random coincidence, or does the SFP rate select actually do something for (some) good old 1G SFP modules too? I don’t want to try again as it might break 
My understanding is that this article applies to 10/25Gb links, and I have only 1Gb here (CRS328-4C-20S SFP port with SFP module - Netpower Lite 7R SFP+ port with SFP module).
Anyway, later it turned out that changing the rate select setting stopped the packet loss only temporarily. It was just a reset (link down/up) and the packet loss issue came back after some time.
Another thing I’ve just tried - change from auto-negotiation to forced 1Gb on both ends - and this seems to have stopped the packet loss for now. Will need to wait longer to see if it’s really a permanent fix.
On the other hand, forced 1Gb is not a cure for all issues - the other SFP+ port in the Netpower Lite 7R is connected to FTC11, worked fine with auto-negotiation, stopped working with forced 1Gb (link shown as up, but no packets received).