—”In the USA, most electricians are using more aluminum these days due to the cost of copper.”
For residential?
Perhaps where you live?
I’m related to two electricians and hear about it often.
“The wiring itself isn’t a problem; aluminum conducts electricity safely. ... The U.S. Consumer Product Safety Commission (CPSC) reports that homes with aluminum wiring are 55 times more likely to have “fire hazard conditions” than homes wired with copper.”
For circuits 30 amps and larger, aluminum is commonly used.
Even in commercial. There is a product called aluminum MC cable, I know of one 40kVA UPS installation that used 1/0 gauge aluminum MC cable.