You built your application and suddenly customers start complaining not being able to load your website. This is where you need metrics of your application minute by minute. Timely right info can mean faster fixes.
Project planning involves looking at metrics from past projects. This can lead to better estimations, correct resource allocations. Viewing your current buckets of work leads to better informed decisions.
Your sales react to local & global events on a day to a basis. For an example, Thursday 3PM - 4PM might be your best sales day. You would want to know, reaction to a social event that brought an undiscovered item to high sales volumes.