In the 1990s, the Internet was, to put it kindly, not quite all there yet. Amazon was still best known as a rain forest and Alta Vista was still somehow the search engine of choice.
For Magic: The Gathering players, the explosion of the game and the growing number of tournaments meant a growing number of statistics building up. While available online, most users still had no real way of finding out what their ranking was or what their win-loss record was.
So, Wizards of the Coast teamed up with MCI to do one of the most '90s things possible: create phone cards to call into a special MTG phone service to find all that out.
In 1996, phone provider MCI became one of the first sponsors of the Pro Tour. Some cross-branding was needed, especially with ESPN now showing interest in televising some events. However, a phone company reluctant to get into the cell phone market and a card game that didn’t exist four years prior didn’t have a lot in common. That’s where phone cards came in.
With a lifeline now set up to call in, Magic phone cards began making the rounds in the mid to late '90s. With each card adorned with artwork from Magic cards, the phone cards themselves began to be somewhat collectible. They were even given out specially to DCI Legend Members.
By 2002, the phone cards were available in 30, 60, and 100-minute amounts, because (apparently) some people apparently needed to know their changes in rankings a lot.
2002, however, turned out to be a tumultuous year. The Internet had grown by leaps and bounds and most players were signing on there. MCI had also gone bankrupt, effectively putting their deal with Magic on hold. While phone cards could keep being used to the end of the year, it nonetheless ended the game's unique phone-in service and cards, thus making any remaining non-connected players learn the wonders of dial-up internet.
DCI stats from then until May of 2020 could be checked online before another shift to an app was made to basically fulfill that need.
While phone cards have pretty much gone the way of the Nintendo tip hotline, it still remains a unique part of Magic: The Gathering’s history and is a testament to the game's longevity.