They're meant to replace the A-10 eventually, so yes regularly would be appropriate. At least: "its in the expected role of the airframe"
Whereas an A-10 may roll in for a gun-run at low altitude the F-35 will be dropping precision SDBs (Small Diameter Bombs) from high altitude instead.
I would be astounded if the F-35's gun gets anywhere within spitting distance of "regular" usage, especially since getting into gun range puts your exceedingly expensive plane into range of MANPADs.
I agreee that it is a requirement of the design but I have serious doubts it will ever be actually used that way.