I went into software instead, but IIRC sales and QA engineers were common jobs I heard about for people in my actual accredited (optical) engineering program. A quick search suggests it is common for sales engineers to have engineering degrees? Is this specifically about software (where "software engineers" frequently don't have engineering degrees either)?
In my (software) organisation, sales engineers were not aware of the fact that after entering a command on a linux terminal you must press enter for it to work.
They were also unaware of the fact that if you create a filename with spaces you must then escape/quote it for it to work.
They requested this important information to be included in the user manual (the users being sysadmins at very large companies).
In the places I've worked, sales engineers are similar to consultants. They work with the sales team to produce a demo for a prospective customer. They need to have development chops to do any customizations, produce realistic sample data, and need to understand the architecture of the product to make a compelling demo. They also need to have the social skills to answer technical questions on-the-fly.
Yeah where I work they have no idea about development. What they do is more like write in the chat saying stuff like "I have a 100% guaranteed sale to the biggest customer ever (which is usually bs), now implement this incredibly complicated feature within this week!"
Actually our sales INCREASED when they fired like 100 of these guys :D