Trams are, as you’ve noticed, a different usecase - subways are for getting you from A to B quickly, and trams are for getting you to the subway stop/straight to your destination on a shorter trip. One prioritises speed and throughput, the other - access and ease of use. Both should be used together to form a good transportation network, with buses and trains going to more remote/less dense areas.
Trams are, as you’ve noticed, a different usecase - subways are for getting you from A to B quickly, and trams are for getting you to the subway stop/straight to your destination on a shorter trip. One prioritises speed and throughput, the other - access and ease of use. Both should be used together to form a good transportation network, with buses and trains going to more remote/less dense areas.