The Capt guards the tiller until the 80kt call at our airline in the 747 - if you lose the critical engine you'll need the tiller to keep it on the concrete up to around that point. It's also a check for power set/throttle hold as previously mentioned.

The flying pilot has the rudder, the FO will hold nose down on the yoke if the Capt's flying. If it's the Capt's leg they'll move their hand from the tiller to yoke at 80 kts.

HTH
Spongebob.