> notebooks are hard to sterilize

There isn't a library of lab coats which contain notes written on them, for future consultation.

A notepad page is also easier to permanently sterilize (via incineration) than a lab coat.

The commenter acknowledges this: "I was always impressed that the laundry managed to get them pristine white again."

I think it's pretty clear they were taking ephemeral notes, not using them for long-term archiving.

The labcoat is a kind of L1 data cache.