Need? No, of course not. But it simplifies an assortment of things and once Matter is more broadly adopted, setting things up fully local will be a massive improvement and future-proofing.

The big players are signaling that they are not making money on voice, so I'm expecting them to start charging or give up (typical Google answer).

A few of my use cases:

• Litter robot is in error or offline state for 30 minutes, toggle power
• Easing of light intensity and color as sun sets daily
• Vacuum when we're gone and it's between allowed hours.
• Return vacuum to hub when we return home
• Turn on lights so vacuum can "see"
• Improved environmental control because I have better presence detection using HA than Nest.
• Turn off power for cable box if conditions are met (otherwise it's nightly updates and reboot illuminate the bedroom at 3 AM.

Personally I think notification is the potential life changer most people don’t realize. Imagine an easy way to tell when the laundry is done without that godawful buzzer. Did I leave the stove on? Is there water in the basement? Is my fridge out or otherwise not leaping cool? What about my garage door? Is the hose running?

A house that can let you know when something is wrong would be huge. Today, a few techies can make that happen with sufficient time and effort. Matter can make that straightforward for everyone. My Mom could never understand Home Assistant or all the components, but she can act when the house tells her she left the oven on

I guess people don’t need it. But there are nice efficiency gains when automating certain parts of the home like heating or cooling.

I've gotten into it. There are a few automations I like, such as a single button to turn off all the lights when I go to bed. Or for the robot vacuum to clean when I leave the house.

Even with that, I could totally live without any of the smart stuff.

I would like my lights to be brighter during the day than they are at night. And if I'm sleeping at home, I'd still like enough light that I'm not stumbling over the kids toys when I need to pee at 3am.

If I'm watching TV and it's a bit cold, I'd like to be able to adjust the temperature from the couch... and in summer I'd also like to be able to cool the house down when I leave work (and when the sun is shining on my solar panels) rather than firing the air con up when I get home from work and the sun is no-longer on my solar panels. If the smoke alarms detect a fire... I'd like to be alerted even if I'm not at home so I can check a camera and call emergency services to put the fire out before everything I own is destroyed. And I hate the fact that my fridge uses a huge amount of power at night when my solar panels aren't powering my home... it sounds like this new Matter standard will allow me to adjust the settings on the fridge by time of day which could potentially save hundreds of dollars per year.

Do I need all of that? No. But I'd like it.

The way things are right now, if a device is going to have a "smart" feature, then the smarts need to be in the device. For example some very expensive fridges have a full control system on the fridge that can be used to configure the defrost cycle (defrost uses a lot of power and commonly runs hourly). With Matter those smarts don't need to be on the device - they can be on your phone or your TV or a home server.