The only positive thing is that this group appears to have been too inept to inflict the amount of carnage that was possible. Multiple bombs in multiple high traffic areas. This could have turned out much worse if it wasn’t for the bomber’s ineptness. A more highly trained group and we’d be counting the fatalities in the hundreds.
You’re right - it could have been much worse... I doubt we can count on ‘total ineptness’ in future attacks, but we can be thankful for it this time.