I think the timing of this reveal is very well chosen.
it says to the American that even if you leave the region we still can get to you with our ICBMs.
Iran was bullshitting the world with its 2000 KM missile range because US bases are close, and now that they will leave (in peace or in pieces), they are revealing the public secret that iran has ICBMs that can hit every square inch of the US soil.
Moreover, there is a Libanese political commentator named Anis Naqqach that has very strong ties with the IRGC that said that Iran has missile farms in Venezuela that can hit the US, and that all the US oil rigs will be melted if the US attacks iran or Venezuela oil infrastructures (he was commentating on Iran sending oil shipments to venezuela and US threatening to hijack them).
There is another Libanese political commentator named Nacer Kandil with strong ties to the IRGC that also said that Iran told America and the west that if Iran is nuked, it will make a nuke in less than a week and will nuke everyone that attacked Iran.
He said that Iran told America that the Fatwa about nukes being forbidden will change the second Iran is nuked.