Enterprise Activation is the process by which you connect and configure your BlackBerry to your company's BES (BlackBerry Enterprise Server) wirelessly. Sets everything up for you.
Does your company have a BES, or is this a personal BlackBerry? It is also possible your company did not invest in a BES and simply uses the BIS (BlackBerry Internet Service), which does not use EA.
Benefit of BES (BlackBerry Enterprise Server) is EVERYTHING is wirelessly synced! It's brilliant...
Not sure about faster for web pages, since that's determined on your connection, i.e. Wi-fi, EDGE, EvDo, etc, etc. But, the restriction on BES is that the owner (your company, since they are the one's who normally have this) can restrict things, like application installs, websites that you can go to, etc, etc...
Other than 100% wireless sync (which I am by no means discounting!), the primary benefits of BES are on the administrative side, am I right, Navi? Remote policy push, remote kill, restrictions on media card usage, mass storage mode, bluetooth, etc...
Hmm, that's kind of exactly what you just said, isn't it?