1)They had busy all their builders facilities ,and will have been more expensive to build one ,since it
will have required to build new naval facilities and start a new design and build from scratch everything.
Will have been far more expensive to build it themselves and slower is is done from zero.
Actually it might have been cheaper to build it themselves.. the problem was time... it would have taken 5 years at least to just get some competing designs together, with 3-4 years to test and decide which they will build. Add to that another 5 years to build and test and fit out and it would not be ready before 2022 and event then there is no guarantee it will not have any fundamental problems in design.
this way they get a ship with all the problems sorted out and fixed and ready for handing over this year...
2)Will allow Russian Engineers to learn how France do their warships ,and learn new ways to build modern warships
that will significantly enhance their knowledge on building warships in a more elegant and modern stylish way. I will have preffered however the Spain transport ship is far nicer looking and allow vertical landing planes too ,in case Russia in the future build them.
that is a valid point, though the South Koreans building a shipyard for Russia will also help them learn new modular production techniques too.
IF france cancel the deal.. it will not matter for Russia ,because their Engineers already saw the whole thing how France do it.. so will be far easier now for Russia to do it themselves ,without having to reinvent the wheel . But as a bonus Russia could the mistral much better ,with the capability to operate in the north Pole ,break ICE and even carry weapons.
The French will have handed over the blueprints and production techniques etc etc already.
The Russian version of the Mistral will be designed for arctic operations and Russian helos and will all be equipped with Russian weapons.
What will be nice for Russia to do is an aircraft carrier that can operate as submarine too.. That is Submarine First and warship second..
The main problem there would be size, and the vulnerability of the vessel during surfacing and submerging procedures.
A sub like Typhoon with the main tower offset to one side and a landing strip added to the top of the deck for UCAVs would be very interesting... but I rather suspect that replacing all the missile tubes with UKSK launchers... say 40 of them, and S-400 and S-500 launch tubes there as well would be rather interesting. With 40 UKSK launch systems that would be 320 cruise missiles, plus say 256 S-400s and 12-24 S-500s would be a formidible loadout that would allow the land attack of most countries plus the potential for airspace denial to create no fly zones in the middle of the ocean.
of course to operate the S-400 and S-500 properly it will need radar intel, so a Ka-31, or UAV based high flying radar equipped aircraft would be needed...