Really?
I suggest you forget the word convenience ASAP. Only legal requirements matter, mate. Get used to it.
My company uses the verbiage required and desired in a legal document called the GMM that lists the aircraft library. It is amazing how many documents are just "desired". But I will say that an all fleet's Boeing, MDC and Airbus one QRH is required. You have a narrow minded attitude and I had mixed feelings about replying to your rubbish.
Bottom line is Boeing or MDC may have never suggested a QRH for aircraft like the DC-10 or B727 so there may be many operators out there today operating without a QRH. As I have heard in this thread Airbus is big on them.
I would give the advice to anyone who has a question like this to ask you friendly AMT/AME. I am sure a GMM or document prescribed by your CAA that is similar to it will reveal all the documents that are required to be in the cockpit of your aircraft.