Using "doctor" as a title or a form of address is common in the academia, including in the US. It's also very formal, especially in spoken language. Hearing it in situations where such formality is not expected can be awkward and embarrassing.
I only ever see it with people in the humanities. In science... weird - more than weird, in general seeing someone who uses the Dr. title is a good indication of "you're going to read the worst shit ever hidden under an insufferable amount of vague verbiage".
To give another data point: in France I remember the university having to ask the local profs. to put their titles (Dr, Prof, etc) in their mail signature as otherwise students thought that french teachers were much less competent than e.g. teachers from germany who would have three layers of Dr. Eng. prepended
One common situation is introducing an invited speaker at a conference. After the first mention, you refer to the speaker using a mix of pronouns and names. Full name or last name would sound weird. Using first name works if the speaker is your friend and many people in the audience also know them as a person. Otherwise "Dr. Lastname" is a reasonable choice.
Academic websites are full of short biographies of speakers, lecturers, PIs, and so on. They are often written in third person. Again, "Dr. Lastname" is often the form of reference that sounds least weird.
Academic spam is often addressed to "Dr. Lastname", especially if the sender is asking the recipient to do something. Using "doctor" as a title is a safe default choice. It sounds respectful, it's very likely to be correct, and it saves the sender from guessing the gender (and possibly marital status) of the recipient.
