I would love to see how my pace / heart rate changes during my long runs or races.
How I performed on the first kolometer compared to how I performed on the last one.
So I would use some button in garmin connect, that would allow me splitting the activity to laps by 1km or 1 minute for example.
I know I can set it on my device (910xt) before the workout, but I prefer not to use my device for it.