Re: high arc / bullet drop as an tactical advantage?
Indirect fire esoterica is neat to know but not often used. Ladder sights (like on the Mauser 98K, Springfield, and BAR) went out of favor in the US once the Army adopted the M1.
Interesting, sure. Fun, definitely (search for the article by Colorado long-range shooters who kill prairie dogs at 2,500 yards with a .308). Usable, maybe. Worth spending lots of time on, no.
High lofting trajectories expose the projo to winds longer.
Cardinal rule for mortars and high-angle fire is to use the lowest possible angle and charge to minimize group dispersion.