Muscles are different between genders, on average.
A woman's 1RM is a lower percentage of her body weight than a man's (on any exercise, on average), but she will usually be able to do more reps at e.g. 70% of 1RM.
So it makes sense to exercise that higher endurance, and kettlebells are very nice for their mix of strength/endurance work.
(I'm male and love both the barbell and the kettlebell).