Bag-drop and gate-close deadlines are set relative to your flight's SCHEDULED departure time, not its live, possibly-delayed one. A live delay doesn't move these deadlines unless the airline has formally retimed the flight in its own systems.
A delay you see on a tracking app isn't guaranteed - flights recover time, gate assignments and boarding can still proceed on the original schedule, and airport/security operations are staffed and queued around the scheduled bank of flights, not each individual delay. Treating every reported delay as free extra time is how people miss flights.
If your monitored trip's flight is formally retimed (not just showing a live delay), this app's monitoring will reflect that - but even then, any gain is deliberately capped at 50% of the delay, since a formally retimed flight can still move earlier again before departure.
These are general, statistically-modelled estimates - not a guarantee. Always allow extra time for anything unusual, and check your airline's and airport's own current guidance.