As the splitter rises in popularity, why do left-handers rarely throw the pitch?

The split-fingered fastball is the "it" pitch right now, but it is still rarely thrown by left-handed pitchers. Why is that?
The Boston Globe

Brody Bumila is 6 feet 9 inches and his fastball touches 101 miles per hour. Could MLB come calling?

ATTLEBORO — First pitch was minutes away. The starting pitcher was done warming. The loudspeakers at Bishop Feehan were pumping Kesha’s 2010 club anthem, “We R Who We R.” Brody Bumila exited the home ...
Major League Baseball

Scott's revamped pitch mix key to electric start to '26

This story was excerpted from Anthony DiComo’s Mets Beat newsletter, with MLB.com's Jared Greenspan filling in for this ...