The Vicar
as any rules of thumb, there are limitations: it's up to you when the rule is good or not for you!
In a cat C aircraft at 120Ktas you are stabilized at final approach (or stalled,depends on weight)really doesn't matter how much is your turn radius (infact is 0.83Nm).This rule (Tas/60-2)is very handy during intercept of final courses, at arange of speed of 180-250 or more.