getting a Teams license doesn’t get you everything else in the M365/O366 ecosystem - not by a long shot.
And his point about SharePoint is weird. The backend file storage of Teams IS SharePoint, to the extent that when you go to the file tab in Teams it gives you the option to “open in SharePoint” to see the file library.
I bet half the stuff he showed you requires additional licenses if you want to do it in Teams - did he show you ADO bots or PVA or PowerApps or Forms surveys? All those = extra licensing.
That guy is an idiot, or a lying sales guy, or both.