There's all kinds of pros and cons to each type of system. And each factor may or may not be an issue for everyone.
Very high efficiency speakers capable of very high SPL *might* not measure as well/ accurate as lower efficiency speakers (less than 92dB/2.83v/m) like TAD CR1, KEF 201/2, Salon2. They may or may not sound as good to some people.
Everyone agrees that having multiple subs is advantageous. When budget & space are limited, do you go with less subs and more towers vs more subs and less towers? For example, having 5 monitors on stands atop 5 subs spread out in the room (3 front + 2 rear) may require less space than 2 towers + 1 center + 2 surrounds + 2 subs. And with 5 subs (instead of 2) the bass *might* be better.
Some towers may cost 3 - 4 x the monitors, and the money saved would go towards subs.
Some debate that towers sound better than monitors, while others feel the opposite.
You just have to see for yourself.
Personally, I see no advantages of towers over bookshelf + subs.
I prefer [5 bookshelf + 7 subs] over [5 towers + 2 subs].