Well, it's not simulationist/realist, it's game balancing/meta. A way to let characters of different terms and rolls hang in the same party. It could be stated differently as "after connections gain Jack of all Trades at 4 minus highest skill rank" if the expression was the only problem (though I gather it's not).
My most frustrating experience with Traveller was a Classic game where I went Scouts, failed the first term survival roll, then found out the GM treated a failed survival roll as mustering out and entering play. Meanwhile someone else was rolling in the corner chortling to themselves, and came up with the stereotypical retired admiral. "That's realistic, of course the Admiral has more skills than the one term Scout!" Yeah, but realism wasn't my problem, nor was my problem that we weren't perfectly balanced, my problem was I was worse at literally everything, including my two skills, than the admiral was.
Nevertheless, this answers my question. It raises a separate question, though. Do you guys balance player characters against each other in any way? Limit on the number of terms, rolling a second character if you're not happy, something else? If one player gets the short end of the stick somehow, is that just their fault for not nudging the dice and you assume they're playing what they want to, or no?