If ever such column will be added in the Tasks tab, the displayed value could be the difference ("CPU time at last checkpoint" - "CPU time"). For strategic games like "do I shut down the client now, or should I wait a bit more..."
(BOINC client devs are not willing to add something like "Pause each running app after reaching a checkpoint".)
(BOINC client devs are not willing to add something like "Pause each running app after reaching a checkpoint".)