Dani,
The main drawback is that they try to teach you the system in another way then Airbus does
hate to be the bearer of bad news, but having flown most airbuses myself (and some boeing), Airbus does not intend to teach you any of the system from the fcom (written very badly). Some of us on the other hand prefer to understand how the systems work not just pushing buttons. I see you agree with me on that part but Airbus prefers the other option. Follow ECAM, Push buttons only.