Uhh… they’ve always been canon to the movies. Remember when Agents of S.H.I.E.L.D. was cleaning up the mess left behind from Thor 2? Or the constant references to the Battle of New York? The Netflix Marvel shows made references to the MCU films all the time.

It’s the reason I preferred the MCU over the DCEU. DC’s TV shows had absolutely nothing to do with their new movies, so they didn’t contribute to the world building. It felt pointless to watch stand-alone series that went nowhere, so I skipped them all. But the Marvel series were all set in the MCU, so it was developing more heroes who could potentially make cameos on the big screen. Or further developing heroes who were previously on the big screen, like Wanda, Loki, Phil Coulson, Hawkeye, etc.