The principle on which this separation is grounded is the principle that you should attempt working with what you can actually influence. It is often not in control of marketing to heat up leads to the state of a sales opportunity. The rule is that the bigger the check – the more needs to be cleared out with the details from an actual human being.
The average check of an internet purchase in 2022 is less than $120 USD. Meaning, that if products cost much above that, it is much harder to convince a purchaser to pay online with no human interaction.