Is there any obvious advantage for monoblocks?

CHannel seperation for one. You would be limited now by the source. Great for imaging no question. If you even have the luxury of having 2 dedicated 20 amp circuits, that can also be a small sonic benefit for maximising juice per amplifier. If you have the money to spend, its a nice situation for extracting every last ounce of potential for your system. =)

monoblock offers you better control. you will have good quality bass. But this may be in the expense of good quality high and mid.

Shorter speaker cable runs too!

the myth of channel separation is just that...but they look way cool.

High power capability, that you can still pick up and carry.
Short speaker wires/long interconnects... probably a wash.
Separation (low crosstalk) is a myth unless your stereo amp is a clunker.