A VTOL requires a 1 to 1 thrust/weight ratio or more.
A normal airplane requires a 1 to 4 ratio while climbing and just 1 to 10 for slow cruise at best L/D.
It would be inefficient to run the large lift engine for slow cruise.
The high speed military VTOL airplanes need about 1 to 1 thrust for cruise, so it makes sense to use the same engine for lift and cruise.
Transport VTOL (see Dornier DO 31) designs usually have separate lift engines for takeoff and landing and yes they are just dead weight in cruise.
I am working on direct lift for the low speed range only, not interested in high speed.
So there is no need to tilt the lift system for cruise. Some tilt for takeoff or landing is desirable however.