You can see all of your customers in one place - not just those that have been contacted by sales but also prospects who are interested / looking for information about you product or service etc! It's very easy to use as well once set up correctly (if it isn't already).
I think there is now more competition with other platforms out their so pricing could be better? But still good if this works best within your organisation/budget constraints. We were able to consolidate our contact activity from multiple databases into 1 platform which was previously spread over 6 different systems we used internally & externally via campaigns sent through Hubspot.