I didn't think a compression fitting was used on gas lines in 46.
Anyway I gave my idea to prevent leaks. You don't know what country the valve is from. Or what packing is used and the vendor does not either. You are correct in worrying about leaks.
Better safe than sorry.(or original)
If a person does not want a chance of leak, use a hose bib pipe fitting out the bottom and forget the valve. The valve is 100% absolutely unnecessary.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn