Sensorless bed probing has been used on a Cartesian machine and it is configured by using P10 in the M558 command. However, a delta printer does not have sufficient Z resolution for it to work. The Z resolution of a delta using belt drive is at best 12.5 full steps per mm. Stall detection is accurate to +/- 1 full step at best. So you would get height errors of up to about 0.1mm.
It's possible to use stall detection to replace homing switches on a delta, but only if you then use a Z probe to run a quick calibration cycle.
btw I am surprised to hear that someone used stall detection on a Smoothieboard, because the stepper driver chips on Smoothieboard don't support it. I guess they must have used an external driver.