At high temperatures this is of course a nice safety feature, but for low temperatures this is principally used to maintain visual on the reaction itself, which is the prime reason to use a glass reactor in the first place. At the image underneath, a jacketed reactor and a triple wall reactor are both cooled down to -25°C. The jacketed reactor is completely covered by ice while the triple wall is still completely transparant.
For any thermoregulation tasks, the triple jacket will have significantly shorter cooling/heating times. E.g. when using a Unistat 405 to cool down the triple wall reactor of 2L to -25°C will take only about 30 minutes, something that is unthinkable with a normal jacketed reactor.