When should I use flight alerts versus flight status?

Flight Alerts:

Please use the FlightStats Flex Flight Alert API if you want to set up a flight rule and want to be notified only if something of interest happens. Example: I want to be emailed if my flight departure is delayed. If the flight is not delayed, no notification is sent. You will receive a separate notification for each triggering event that occurs. Here are the alert callback events that you can monitor:
https://developer.cirium.com/apis/flightstats-apis/flight-alerts#section/Alert-callback-events

Flight Status:

Please use the FlightStats Flex Flight Status API if you want to perform arbitrary flight status look ups at any time to check the current status of the flight. Our system returns the available flight status data and you scan it for what you are looking for. Example: I want to know right now if it looks like my flight will depart on time.

More information on the Flight Status Response Elements see flightStatus element under the Response Schema section under the following links:

https://developer.cirium.com/apis/flightstats-apis/flight-status#tag/By-airport

https://developer.cirium.com/apis/flightstats-apis/flight-status#tag/By-flight

https://developer.cirium.com/apis/flightstats-apis/flight-status#tag/By-route