We're nearly there!
This is the easiest exercise to expand upon. Try some of the following:-
More chords of the same type (try the backing tracks with 4 chords)
More chords of different types (try the backing track with different chord types)
Try playing 8th notes and then 16th notes (still scale based lines though)
I'd recommend that you begin with the same chord types as don't have to worry about the different scale types that will occur if we change chord types. Once you're comfortable with that over a few chords you could go all the way to using all 12 minor7 chords or all 12 7sus4 chords for example. You really know you're getting somewhere when you can play a continuous scale exercise over the same chord type as it moves through all 12 keys.
Bear in mind that this is just an exercise designed to develop fretboard knowledge. In the coming tutorials we'll use this knowledge and help you with note choice and phrasing. Work on the fretboard knowledge first in the same way you learn the vocabulary of a language. It needs to be there so that you can express yourself.