From what I can see - the MSI can be "used" by anyone i.e. History etc- the limitations come when you want the Sales team to begin true SFDC / Marketo integration via Email sends etc.
Hi Anupam-
Instead of controlling it at a Profile level inside of SFDC, you should be able to grant the MSI visual force elements via Permission Set (which is easier to control than swapping Profiles). The current MSI licensing theory is that if you have the plug-in, you should also have the MSI tab and vice versa.
Good luck.