I think the proposed track left a lot to be desired, but there was (and is) plenty of potential for a track in Miami to make sense. As you mentioned, a park (like Bayfront Park, which is RIGHT NEXT to the proposed circuit and has DECADES of history hosting races for IMSA and CART) is a pretty feasible option.

A city multiple times more populated than St. Pete has its share of drawbacks. Namely thousands upon thousands of residents right alongside the track. St. Pete’s indy course runs mainly on airport roads if I’m not mistaken.

That isn’t the Macarthur. That’s the bridge to PortMiami, which - while still active - is no longer the primary entrance to the port. The PortMiami tunnel was completed a few years ago and runs directly off I-395.