Eh, what fireflies can do is kinda the base level of the bioluminescence 'skill' of the evolutionary tech tree.

https://gizmodo.com/glowing-deep-sea-squid-have-a-complex-form-of-communica-1842472534

https://youtube.com/watch?v=DE89YY7zCio

Humboldt squid skin is bioluminiscent, but roughly akin to a flexible lcd or oled screen, with many different 'pixels' capable of being set specifically.

They likely have the ability to communicate by basically displaying different patterns of different colors and brightnesses and translucency, sorta like a human walking around with a sandwich board made of lcd screens, which they can control with a phone app.

They may very well have an entire language they can convey via sequenced or at least specific patterns.

Note: No clue if you can actually trace bioluminescence in fireflies and certain cephalopods to the same common ancestor or if its completely different, independent evolutionary occurances, but my point is there are certainly more and less complex and utility granting forms of bioluminescence.