When millions of AT&T customers across the country briefly lost their cellphone service last month, Francella Jackson, 61, of Fairview Heights, Ill., said she picked up her well-worn Southwestern Bell push-button landline phone and called her friends “just so we could laugh at the people who could not use their phones.”

“Why, isn’t it great that we can talk and have a great conversation?” she recalled saying. “We had a good laugh.”

Derek Shaw, 68, of York, Pa., said he has an Android mobile phone, but prefers talking on his black cordless landline at home. The sound quality is better, he said, and the phone is easier to hold during long conversations. Mr. Shaw said that he also likes talking to people face to face rather than on Zoom and never got rid of his vinyl record collection when CDs got hot in the 1990s.

“I’ve never even thought about giving up my landline,” he said. “I’ll go kicking and screaming when I have to.”

To many, landline phones have come to seem as essential as steamships and telegrams in the smartphone era. But to those who still use them, they offer distinct advantages. Prompted by the AT&T outage on Feb. 22 and a push by AT&T to phase out traditional landlines in California, those who have them are speaking out in defense of their old phones.