Absolutely, but there are many FBI employees who are not traditional SAs.
If you have a military background, think of them as sort of like Warrant Officers in the Army.
For example, they have surveillance specialists who are incredibly good at foot and car tracking POI. Some are old people or have other characteristics that would lead a POI to dismiss them as tailers. They are also usually very mobile, often single, so if suddenly 10 new tailers were needed in NYC for a case, they could easily be flown in from LA or Boston. Most are also pretty good actors, accents, etc, and good high speed drivers.
Then there is the JTTF, 13,000 agents at last count. Lot of Feds, but also a lot of current or retired, highly experienced street cops, especially plainclothes types and experienced detectives. They “Know the turf.”
Thank you. Very interesting info.