Having to disinfect 'every day' seems a bit of an exaggeration to me - in my experience it's rare to see an attempted infection (other than false positives) more often than once or twice every few months unless I'm on particularly seedy sites, and I'm pretty confident that there haven't been any unnoticed infections too. However, based on personal experiences of running without an antivirus, that's basically just inviting any old virus in and does lead to a lot of easily avoided hassle.
There may indeed be some benefits to Avast's connectivity options, but the idea people seem to be spreading that the software is not complete without them is worrying, because I'd rather my antivirus still work to a reasonable level when I'm not online! 
Bandwidth isn't an issue here, at least not in the sense of any kind of data cap, but I generally prefer to have as little going on as possible, to reduce interruptions during gaming and just for kinda OCD reasons.
I do understand what you're trying to do here.
Still, as the majority of your unknown and undetected connections never will come up when one is offline, and that also would be true of avast! operation under the same scenario, I don't think any connection issues would apply here when offline. I do think avast! is natively set to run these sort of connections by default only when one is online. You are also questioning why there is a need (and so many of them) for such connections in the first place based on your needs and use of your system.
I'm OK with that.
All one has to do is look back to version 4.8 free to see the difference between that old version and the current one, version 8.0.
Glad avast! can be customized specifically for each user if they so desire. I fear, though, most users that attempt to do these sort changes to the default connections will go too far and then wind up in a troublesome situation that could easily have been avoided if minimal or no changes had been made.
As long as one has an imaging program set to back up their operating system drive on a daily basis, this sort of trouble can easily be undone, and then one is certainly free to experiment with these sort of changes as much as they wish.
Given the extensive modifications and the addition of many new features, I think the avast! team has done a terrific job integrating them all and, also somehow managed to keep their program from noticeably impacting normal use of a system for the vast majority of users. I can attest here that impact on start-up time, is, at the most, only 10 seconds or so, and on normal operation, negligible.
And, they're still supporting XP. (And Win 2000, as far as I know)
[EDIT:] Following up on bob3160's advice, why not temporarily disable avast! when you are playing a game
and offline?