I can only think of one activity where tongue endurance is important, and I guess it's good that runners come out ahead in that department.
I can think of another — sleeping. A doctor named Mike Ilkes published a book claiming that snoring is mostly caused by weak muscles in the tongue, soft palate, and lower throat, and can be cured through simple exercise. I can't vouch for the veracity of his claims yet, but ask me again in a few months… https://www.telegraph.co.uk/health-fitness/body/simple-worko...
Im overweight and snore as a result, or have sleep apnea or whatever. Tongue Endurance might okay a small role but its not helping me. I am a beatboxer and consistently train my tongue and muscles around the throat.