My sim gets promoted in the same time as finishing their degree.

The O.P. point is very valid though. While TS2 gave us new 'university locked' careers and an incredible jumpstartstart (as much as reaching lvl 9 of a career, or 8 for uni locked ones), TS3 gave us an incredible raise in salary that you simply couldn't match by going to work for the same timespan you would earn your degree. In TS4, My main sim has career hopper, which gives (incredibly) better job perf and doubles salary for ALL jobs. So unless the benefits of a degree stacks with that, going to Uni is more a personal preference than a wise game decision.