If someone is making time commitments to customers, then they aren't in marketing...they are sales.
Sales and Marketing are grouped together as marketing is a support function for the sales organization, but they are NOT the same. The marketing team develops the brochures and the data sheets and customer testimonials, magazine ads and editorials, whitepapers, etc. that the sales person never reads, but passes around to the customers, and talkas around effortlessly.
The sales guy doesn't really need to know how the product works, because he knows how the customer thinks, and uses that to sell him. The fact that they are able to sell multi-million dollar systems without knowing what they do is precisely why they are worth the big bonuses and such...because regardless of whether the product is good or not, they can sell it and keep everyone else in the business working.
Engineers are fantastic and building things, and I wish I had developed the aptitude to become an engineer when I was young enough for it to matter, but I've not met the engineer who could sell a glass of water to a man dying of thirst in the desert. Technology doesn't sell itself. You could have the best product in the world, but without salespeople and marketing folks figuring out how to sell it to someone, you will go out of business.
Case in point, Digital Equipment Corporation had the most advanced microprocessor technology in the business, full-blown 64-bit architecture all the way back in the late eighties with it being market ready in the early 90's...unfortunately they hadn't the foggiest idea who might want it or why. They sunk millions upon millions and perhaps billions of dollars into a technology that no-one wanted. Add this to a large number of other huge marketing errors and it explains why Digital, the second largest computer corporation in the world, ended up getting bought out by a PC company, which then got sucked down by the weight of Digital's huge engineering tail and the inertia within it.
All that said, salespeople are a pain in the ass.
I'm a marketing guy.