So it has jet engines that blades unfold and attach to during takeoff and landing? Why not always use the blades?

Speed and efficiency I suspect

Targeting a propeller for both raw lifting capacity as well as speed is quite difficult. I suspect they have different geometry as well.

If you spin a propeller fast enough the tips break the speed of sound, from what I recall that knackers the efficency. To generate lots of lift a bigger rotor is more efficient (hence why helicopters have long rotoblades that don't spin at high RPM)

The longer the blades the faster the tips, which means there is a tradeoff between thrust and speed of the air being yeeted out the back

My armchair general understanding: airspeed at blade tip can't be supersonic all the time, and that caps the max forward speed for prop driven aircraft. Same don't apply to jet engines with air intakes that can restrict and slow air flow

stealth