It's value would mainly be to show that we can afford to do some luxury science and local science, and be a focal point for Puerto Rico, which isn't necessarily bad.
If PR had representation in Congress, Arecibo rebuild would be an easy pork barrel project.
The only comparable telescope is the Chinese FAST radiotelescope, which is somewhat larger in diameter but without all the capabilities (and, you know. Being in China.).
Could say the exact opposite... sparse synthetic apertures are more cost-efficient.
Plus, sparse array only works well for high contrast, high brightness sources. And it has a bunch of artifacts that can get in the way of interpretation of the data. Plus just pure filled area matters a lot.