I'm not sure there are any or at least many benefits of using 1 engine. A twin engined boat can certainly be made to do things a single never will.
However, there may be some benefit in discovering exactly what can be acheived, and how, under 1 engine, for the day you have an engine or prop disabled in some way.
On the one occasion i have watched a professional I was amazed that when turning 180 deg under power in a small space he used both engines together all the time (twin screw, single rudder).
It depends how far apart your props are, on my boat berthing with one engine is a nightmare.
I am also fairly new but it comes quick with practice. leave the steering wheel alone set for straight ahead(on a quiet empty bit of water) then put one engine in reverse the other forward and the boat will turn in own length. practice steering a course without using the wheel by doing the above untill direction required is accheived then two engines forward and so on, you will very quickly get used to crabbing using tide, wind and engines for mooring. Just do it slowly.obviously to turn to port requires starboard engine forward port astern etc