Control4, Crestron, AMX, and URC all are glorified universal remotes that fill the massive gap between those who love sites like Audioholics, and those who have never heard of this site, don't care, and will never care... But still want good audio/video in their home.
Someone who loves DiY can do a great deal and may be able to recreate the majority of what any of these control systems can do on their own. It will take them a similar amount of time to do so (after they have learned), and they may have issues go unresolved forever due to a lack of any specialized support for the product they may be using.
I tend to go with this as a mantra: Control systems are not for those who know and love A/V... It's for your parents. It's for your wife. It's for your kids. You already know how to push all those buttons and spin those knobs and you know what that will do. The control system is there to keep the rest of the family away from those knobs and buttons and give them a unified interface throughout the home which is consistent and reliable.
It has also been my experience that the vast majority of people I work with know almost nothing at all about A/V and just want a turnkey solution in what is always a custom environment.
A basic universal remote is not typical of a control system setup. As well, while we have seen a sharp uptick in the number of smart phone controlled devices, they are almost all stand alone applications, which require just as much thought and knowledge to operate as just using the remote of the device itself.
To help give some clarity on this, check out my home setup with two (now 3) 7' tall equipment racks loaded with gear, distributing out to 24 zones of audio with half a dozen (and growing) TVs in the space. It has the flexibility to add new audio and video gear at the rack if desired as well as integration of new equipment. Additional controls have been added for things like lighting, the fireplace, and door locks. I am looking at how to add my garage door to the mix as well.
Why no thermostat? Because I don't touch my thermostat. But, it's possible to do if I want to.
It includes Alexa integration as well and I can expand upon that if I ever feel like it (we don't use it almost ever).
The key thing is that every room with a TV has the exact same remote with the exact same controls and my kids and my wife and my parents can all turn on a TV show or a movie using surround sound or in-room speakers very easily.
https://forums.audioholics.com/forums/threads/so-here-we-go-24-a-v-zones-w-10-sources.83272/