Increased documentation is a cost you pay no matter what, you just pay it later in other formats when in-office - when the SME you treat as a guru finds a better-paying gig you have to scramble to rebuild their expertise from nothing or hope they are nice enough to do a thorough knowledge transfer. That kills productivity far worse and for longer than taking 30m at the end of your day updating some shared wiki.

All this to say, the trade-off you're proposing doesn't exist. You're arguing for paying twice instead of paying once - twice in the sense that you lose productivity now via random interrupts, and in the future when your siloed knowledge leaves you high and dry. Hope the "other things" you got done instead of documenting were worth it in that scenario.