With some accounts being Fundraisers, they won't have gifts in their account, but rather soft credits, this is even more common now with the introduction of the JustGiving Integration. With these accounts they will show 0 in their Giving Summary, because, technically, they haven't raised or received anything and it isn't taking into account the soft credits recognising the hard work these fundraisers have put in getting donations. It means that the tile is only applicable for half of our accounts!
I think it's need to have a column so that we can see at a glance the total amount these accounts have in soft credits, perhaps even having it show under the "Raised" column, because at the end of the day they have raised these funds and it would make our jobs easier being able to see this at a glance instead of having to go directly into the journal every time.
I only just realised this too, after the usual Marathon frenzy. The Totals summaries are effectively useless as although you can see raised and soft credit summaries seperately, when you want a quick glance to see overall total someone has raised, it doesn't show soft credits at all. Marathon runners are a good example, as soft credits come via JustGiving donors but apart from a graphical representation, you can't see a numerical overall total of money raised, which seems daft. The "year to date" total simply stays at zero but yet the soft credits are all in the journal. I've found the only way to see an overall total is to go into Journal add in the "Received and Soft Credit" column. This works, but completely defeats the object of the summary tiles.