I find it a bit strange for a cable company representative to recommend bare wire connections for speaker cables.
Most of the affordable speaker cables use copper as conductors and, over time, exposure to air causes the copper to oxidise forming a layer of greenish cuprous oxide. Cuprous oxide is nowhere near as good a conductor as pure copper, so the oxide film that forms over time can result in poorer connections at the terminals to which a copper wire is attached.
This can be addressed when required by cutting off the oxidised wire ends and re-stripping, but prolonged use of this approoach may shorten the cable too much...
Spade and banana connectors are usually either gold-plated or manufactured from metals that either don't oxidise, or if they do, the oxides have similar conductivity properties as the pure metal. Rhodium plating is one example.
With copper wires, if the connections to the cable are soldered to cover the bare wires, then oxidisation is inhibited, which will maintain the quality of the connection.
So, my preference is to use decent spade connectors which, due to being clamped tighter than bananas, make for a better mechanical contact connection, and then to strip the insulation, insert the fresh bare wire into the holes on the spade connectors and seal the connection with solder.
I hope that helps...