LLMs don’t understand constructions drawings so they’re no help when it comes to doing a takeoff. Construction specifications are already well-organized and able to be searched so LLMs don’t help there.
They can’t synthesize information from different sources (words from a person spoken on a phone conversation, napkin sketches, information that is embedded in an electricians head about a specific facility, etc) or coordinate multiple parties through a variety of communication methods (email, text, phone calls, RFIs, in-person meetings, etc)
About the only use I’ve found for them in my line of work is cleaning up data from outside sources. YMMV. Construction is a very relationship and trust based business that has been around longer than almost every other profession.