Professional jobs are about non-existent in my little podunk town, so I worked fixing computers at that place where they sell staplers for two years. We were never given any opportunity to play with the products so we knew enough to make good recommendation. Some of the sales techs might have a personal interest in that particular area, but we are more often than not reading specs off the box just like you are. Or we can tell you how often particular products are returned along with maybe some customer comments. I could never bring myself to lie and act like I knew what I was talking about to customers if I didn't know, but may of my peers did it all the time if it meant a bigger sale and got the sales/store manager off your back.
Or, many sales techs would lie to sell the extended warranties, service and protection plans. Selling a computer with any extras was a huge no-no because we supposedly lost money on bare units. We would get our hours cut unless we scared the customer into also buying an extended warranty, virus removal plan, in-store setup, office suite and such. If you got them to also buy an ungraded mouse & keyboard, USP, monitor (with extended warranty), a printer (with extended warranty), assorted cables you had really scored a home run.
Some techs would outright lie about crud like customer's old printers, monitors and software would not compatible with their new system even if it was. A system in for repair might be missing a simple networking driver and be unable to connect to our remote technicians for virus removals or other OS repair services, and we were instructed to tell customers the system was not repairable and sell them a new one. Then we'd tack on a $149 fee to pull the personal files off the old system and transfer them to the new system. And then start pressuring for the warranties and other add-ons "so this doesn't happen to you again."
I was the only actual tech employed at my store. Other guys knew just enough to be dangerous or follow the manual for hooking the machines up to the remote techs who did everything. I got on my store managers bad side by taking too much time with customers to explain what they were looking at. I also got tons of flack for doing "unauthorized" simple repairs to customer systems because he would much rather I'd sold a new computer with all the maintenance and virus removal plans.
We were also expected to know about various types of technology but given zero time to actual study or use the technology. How the heck was I supposed to know about a product I'd never used or even touched? I think I watched two short manufacture videos the entire two years I was there and that was supposed to make me an expert on said tech so I could explain, troubleshoot and sell it to customers. No free tech support was another standing order, so if a customer had a simple question we were told to act dumb. Also, when a customer bought a new computer, no mater how much extra they spent on in-store setup, warranties or other add-ons, we were under explicit orders to never, every get stuck showing them how their new computer or Windows worked.
It's a crap job that pays crap, and it's all about pressuring customers into the worthless add-ons. Anytime I made a customer happy I was sure to get a lecture from my manager for taking too long or not upselling enough. It's impossible to be successful at a job like that without jacking over your customers and I was very happy to move on.