Motor sailers are a poor compromise - they are very average sail boats and even less than average power boats.
IMHO, a hybird power plant is the motor sailer of engines.
An argument could be made that instead that the hybrid power plant could actually, if designed properly, deliver on the advantages of of both electric and ICE while mostly eliminating the disadvantages.
Most reports give very high marks to electric drive for, torque, control and sound. In fact just about all the advantages are on the side of electric for propulsion with one exception.
That exception is that power storage in the form or batteries is insufficient.
If you add an Internal Combustion Engine ICE generator that has enough power to drive the motor at whatever percent you feel necessary then you have the range of diesel plus the torque and control of electric.
Along with this design you get some nice added features:
1. The diesel generator can be run at the optimum rpm for maximum life and fuel efficiency. No more idling glazing or running a 80 HP engine to produce 40 HP for days at at time.
2. The engine can be located in the ideal location for weight location and sound control.
3. If the boat is sailing or running off the batteries and you turn on the generator you have a lot of power to run accessories like a dryer, scuba compressor or any other power hungry device you can now have.
But while feasible and super cool if setup right it will not be cheap and probably makes the most sense for a bigger boat especially a larger catamarans where it can even be cost effective for reasons mentioned above.