Our techs are supposed to be crosstrained as secretaries, but not all the US are able to be techs. They do get paid more for being able to do both jobs. When we are short a US, its really tough to keep up with all the orders, so having a tech able to put them in helps.
We nurses were all supposed to take the last computer training when we changed systems, but the newer ones and some of the older ones never got that. I can double as US, if needed. What really made it bad, is when I had to do charge and secretary at the same time! in a level III trauma ER. The docs would give me an order, and then ask who was in charge and do a double take when I said it was still me!
You may well be "sitting for 12 hours", but you won't be sitting on your hands, that's for sure.
And when you do get your license, think of the time and half at nurse's wages to come in for a secretary shift (yes, it has happened to me). That sitting down aspect was actually appealing.