Actually, I'm for this. Though I'm a huge advocate of high activity (feel free to ask any of my old members), I think this could help alleviate some current problems. One being, burn out for serious players. This can be a helpful tool, and although it kind of seems like a cheap way to play to some of the more serious players, it can also be taken advantage of by players who count on players attempting to use this. If you know a player is up late at night and they're making a big attack, you could assume they've queued up a move to fall back after and try to take advantage of the opportunity. And as you stated, sometimes life just simply get's in the way! During those times, I simply killed myself getting online when necessary. This could help alleviate that by a lot.
The other issue being, it might help curb cheating via account sharing. Most do this because of how hard it is to stay active. But with this type of feature, it may make people less likely to resort to cheating first and instead, on this.