Lisa’s video’s are fun..
I try to find a new one every day and incorporate that into my own lessons..

To prove John C’s theory...
this is the C scale, playing the G7 sounds indeed much better..

But then this is intended at starters, yet i personaly think even for starters starting out with the G7 in place works better in the long run... some courses do this while others wait till level 3 to introduce 7th chords..