Comment by beyarkay

(author here) I think there's something to be said for having both (if I allow myself to imagine an unrealistic utopia).

Imagining the distribution of how much benefit novices get out of a scenario, only having the watercooler interactions probably has a high maximum benefit (i.e. there's some expert that loves teaching and puts loads of time into helping novices) but probably also a very low minimum benefit (i.e. there are no experts at the company, or the experts couldn't care less about helping out). So it's the risky scenario, with a high variance.

Only having formal teaching doesn't have nearly as low a minimum (even a lecturer doing the bare minimum is better than no lecturer), but also doesn't have nearly as high a maximum (a high-effort lecturer simply cannot pay attention to each of the 300 students in a lecture hall, no matter how hard they try).

So having the formal teaching raises the minimum, ensuring the worst outcomes are not that bad, and adding in some watercooler interactions raises the maximum, ensuring that high-effort experts are able to converse with interested novices.