It's not critically important, but the many individually small conveniences add up.
Having the lights turn off automatically when there's nobody home is also nice though.
I can assure you pretty much nobody goes to their fuse board and trips the main switch even when going on holiday, much less during their day to day life. Many of the people who don't do that still tend to turn off as much as possible when leaving the house.
And if you're concerned about internet access, there are plenty of hubs for smart projects that don't need internet access. Some don't even need or have wifi capability, but can be wired physically into a dmz with an open source home automation system like Home Assistant. There are USB dongles with Zigbee support as well that you plug straight into your open source based home automation box if you want.
That said: Most people just don't care most of the time, because for most peoples use the worst possible consequence is being slightly inconvenienced.
E.g. should my Lightwave RF gateway get bricked, the worst case scenario is that my Lightwave switches revert to being dumb switches and I'll be slightly annoyed I won't be able to voice control them.
Hardly world-destroying stuff.
What's slightly different here is that this is a new move for Hue (it's not for any number of other smart home providers people happily sign up for online services from), and so some subset of their customers will feel compelled to switch zigbee bridges and incur a cost. (But if you're price sensitive, why the hell are you using Hue in the first place?)
Then I remembered I have cats.
Well, it was reason why it was installed, but what actually was used for is that we set up coffee to brew before leaving work and the timer turned it on right before people started coming to the office so we were welcomed by smell of fresh coffee
But I still don't trust it. I need to do the Japanese train conductor pointing and vocalising thing when turning stuff off when I leave the house for a longer time =)