Originally Posted by
bikerjp
This.
ANT+ is what allows you to connect a heart rate monitor, cadence/speed sensor, or power meter to the unit to record the data. Many cyclists like the HR and cadence data and the more serious ones (or those who like gadgets) use the power meter.
You don't get the full utility of any of that without computer downloads which the Node computers don't do.
(tracking training stress on variable rides, making correlations in the data like you can ride threshold intervals on consecutive days at over 90 RPM but not under, updating interval targets based on critical power calculated off the most recent best shorter and longer efforts, etc.)