Many electricians don't like to use "back-stab" or push-in connectors in receptacles, and prefer to use the screw terminals -- see, e.g., https://diy.stackexchange.com/questions/7977/when-to-use-hol...

https://www.homedepot.com/p/100055784 for example

The lamp sockets I replaced recently also had screw terminals with the brass=hot / silver=neutral convention.