The AFK kick is 1) useless and 2) annoying.
Once capacity is up there is going to be zero benefit of kicking AFK people.
BUT there are about a thousand reasons someone would want to sit AFK instead of logging out. Here are a few:
- just lazy
- want to still get FC/party/LS chat
- let your FC peeps know you online but AFK right now so they don't start new runs etc
- monitor the shout traffic (looking for gilsellers lol)
- want to show of **** gear (saw Towellie idle on Diabolos in his lvl 50 Pally gear last night)
- waiting for duty finder
- RL aggro
- reading ZAM forums (and get lost for an hour)
- i use my computer as a heater and nothing warms me up better than FFXIV on full graphics