It complements https://nuclearsecrecy.com/nukemap/ nicely.
As someone not living in the US, I'd find it interesting to at least have some other non-US cities available in the free plan though.
Something that I always wondered about this tool, and why I bucketed it in my mind as a "cool but ultimately boring toy" - why are all effects perfectly spherical? Surely the actual effect, especially for lower-yield devices, would be meaningfully affected by local topography and even buildings?
I appreciate San Antonio being included, but you may want to shift your exact target a bit to be more accurate. Probably over to Fort Sam Houston, but I'm no expert. Right now it looks like they just really hate the Deco District.
https://www.repi.mil/Portals/44/Documents/Buffer_Fact_Sheets...