Pay for faster Internet?

I recently had serious issues with the Xfinity lines outside of my home. We went through weeks of trying to get someone out here to truely repair it and I believe that it's finally done. The odd thing is that the last repairman questioned my 8 connected devices for my internet speed. I pay for 300 mbps and live alone, have amazon echo devices and some wifi lights. I might leave my Kindle on sometimes as well. He made it sound like I should be paying for Gigabit instead of 300 mbps. Any thoughts? I think he's nuts.