In my country the slashed 7 became mandatory in the national curriculum in the 1930’s. Our military strongly requested this in order to achieve better accuracy in artillery fire control - in those days every calculation was done by hand and mixing 1’s and 7’s could easily have deadly results.
This practice was quickly adopted by the whole population and it was a great success with no drawbacks. The slashed 7 makes it impossible to mix 1’s and 7’s, therefore it is the superior choice.