"britexpat - I find it strange that you need to show your QID at the airport"
The country I come from, security at the airport gate first checks my flight ticket, and visa (Which now is the QID) then again at check-in, my ticket and QID, then immigration checks the ticket, PP and QID.

Second point - "your passport is your main travel document and is linked to your visa and residency " that information is with the Qatar immigration, not at country of origin.
Peace guys,
@ Accha and Brit, I still do not get Rayyan 5 gallon water bottles,