There are two issues with the Recent Activity:
1 - Client communications that take place from within the system. It doesn't show you the actual emails so you know what was sent. This is what is described in the email thread below.
We can't SEE THE ACTUAL EMAIL that was sent out. You're not copied on the emails to the client nor can you SEE THE ACTUAL email. Telling me that they received something and who opened it is fine, but if I don't know WHAT IT SAID (without having to go back and look at campaigns) it doesn't help me.
Nothing is logged under activity, except (1) emails you send from your own email with tracking set and (2) opportunity edits - changed person, changed title, etc.of which only very little provides any value.
Some of the most important things NOT tracked in activity are:
Proposals being sent out so that there is a history of different versions - or even simply so you remember what you typed in the email that was sent with the proposal
Emails from campaigns or automations
Welcome email for dashboard
Snapshot emails sent
Those are just off the top of my head... There is literally no way to see what communication has been sent to clients other than the two things I mentioned at the start of this email.
The problem I see with the comms that get sent out to clients is that it is not tracked in the activity tracker... so you have no way of tracing the history. The activity tracker in each account in the Sales Center just tracks minor things like you changed an Opportunity name or assigned it to someone, along with the emails that were tracked on it.
Nowhere does it log all the other activity that takes place from campaigns and automations... so you never really know what was sent out.
2 - Searching for logged activity. It doesn't filter the information or even show you the stuff you've entered. See video.