There actually is a difference in overall tonnage and displacement, with cruisers being on the heavier end, destroyers in the middle, and frigates (aside from heavy frigates) on the lighter end.
And that tonnage is important.
Cruisers are “independent”, able to run operations on their own or in a small task force. They are more heavily armored and often have more defensive options like point defenses and electronic warfare packages.
Destroyers and Frigates are fleet bound, fulfilling specific roles in the fleet. Destroyers, as their name implies are often for offensive action (anti-sub is a common one these days) and frigates defensive and escort actions.
Then you have fun combos like battle cruisers (which most modern navies don’t run)
Other fun fact, most modern navies also do not run cruisers, with America being the only navy that has a substantial number with the Ticonderoga-class.