I'm not a salesman so I wouldn't know but it seems to me A sales account manager at AcmeTron can dump the entire CRM database, walk it over to WidgetCorp, and run all those same accounts for them without ever once violating an NDA. is the very definition of why you need NDAs.
But again maybe I'm looking at this from an engineer's perspective and it's different for sales.
In either case, I don't think we'll change each others minds here on the Internet.
In a consulting agreement, you may find "Non-use" terms along with "Non-disclosure" terms in the IP language; technically, this would prevent a consultant from stealing the sales rolodex and then using it to contact customers.
Otherwise, you violate an NDA by disclosing to someone not bound under the same NDA actual confidential information. Nothing prevents you from using confidential information to compete "unfairly" with your employer.
You can add whatever terms you'd like to whatever you call a "confidentiality" or IP agreement, but now you're on a slippery slope that leads to de facto noncompetes.
But again maybe I'm looking at this from an engineer's perspective and it's different for sales.
In either case, I don't think we'll change each others minds here on the Internet.