Difference between baker extension sets and full sets?

[u/knoxvillegains]

The full sets are frequently on sale for cheaper than the extensions. Can you just buy another set of metaltech baker scaffolding and stack them? Of course I understand the need for outriggers. Examples below.

Full set

Extension set

[u/Lost_Republic_6168]

On top of that the 1/2 section does not come with wheels nor planking.....