True, they were graded, at a CGC Pristine 10 for that matter, but that's still not a bad return on investment for a Japanese promo that used to be dirt cheap
This allows you to build some insurmountable boards very quickly indeed
In short, it is not simply that unique 4-card caps did not exist, but if they had existed at the time Limited Edition was released, they would have rendered large swaths of the set unplayable in 1993
Studious First-Year Studious First-Year is basically Rampant Growth, a solid ramp spell, attached to a 1/1 creature thanks to the prepare mechanic
Meanwhile, cards with the TRC and SDS symbols are legal in Commander, Legacy, and Vintage, with individual cards being legal where available in other formats
The way these two synergize together is very flavorful and consistent: Rocksteady puts counters on Bebop, which will increase the number of cards that Bebop can draw on doing damage