running in invisible
The game doesn’t have a true “invisible” setting. What it has is a “Greta Garbo” mode: it makes it easier for you to be left alone. For a lot of people, turning off /guild chat is probably appropriate.
However, I think the reason it was done is to resolve a bug with representation: when you’re invisible, the game doesn’t always recognize you as representing the guild. Thus, you might be able to see /guild chat, but not be able to respond. Hiding the chatter prevents the bug, which might have turned out to a more efficient solution. After all, if you’re really invisible, you should really be invisible.
It’s not a bad idea to also hide /map and /say, because some people abuse the invisible status to troll and avoid receiving whispers.
Personally, I like the current system for hiding /guild and allow /map & /say.
If they have the time to work on something, I’d rather that ANet make Invisible more like Offline: your location should always show as ‘unknown’ and you should never get a ‘yellow dot’ on the map showing your location.