Salaried employees aren't paid for their time, they're paid for a combination of their output and their availability. Availability used to be strongly coupled with time but technology has introduced some flexibility there.
Correction: Their PERCEIVED output, not their output. Output can usually not be objectively measured in IT.
Storypoints? Overestimate wildly. Stories done? Split stories like atoms! Impact of work done? Present your button color change stories as company saving divine intervention!
Can you give some examples of jobs that are usually done by salaried employees and are paid by output? All the examples I can think of, are usually done by independent contractors.
I think it depends. Plenty of salaried workers are truly only on the clock when on-site from 9-5