Twisted-wire connection: cons and pros

Good afternoon, dear electricians! I would like to ask you a question as to professionals in their field. My apartment is being renovated, an electrician is wiring in a suspended plasterboard ceiling and twisting the wires together with pliers, insulating them with electrical tape. The wires will then be connected to the fixtures installed in the ceiling, there are about 10-15 of them. Maybe there’s nothing wrong with that, but in the courtyard of the 21st century something is bothering me with his grandfather’s method. Can I get some advice on this. Thank.