I have a Chromecast as well and—prior to purchasing the Roku—used that when I traveled.
The reason I replaced it was because of the purpose it was designed to serve and how I was using it. A Chromecast is a remote viewport, not generally a consumer (save for Chrome and a handful of mobile apps). Take, for example, when I used Plex. I'd have my machine as the Plex server, my phone as the Plex consumer / controller, and the Chromecast as the viewport. All three would be on a private network served up from my travel router, disconnected from the WAN (hotel internet paranoia). All three of my internet-connected devices were required to make this setup work.
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Just remembered the requirement that the LAN be connected to the internet to use a Chromecast. When I'm streaming from Plex, I don't need to be on the internet. Getting connected just so I could then use Plex felt like an unnecessary hurdle.
end edit
Contrast that with the Roku which is not only the viewport but also the consumer / controller. It freed up my phone to remain on the cellular network. I could pass out watching a movie and not have to worry about missing "important" late night notifications / emails.
The alternative was to stream my screen to the Chromecast, but I found that to have tons of lag / frame-skipping.
I have a Chromecast currently, biggest issue for me is that it doesn't support 5 GHz (which matters a lot in a crowded city like San Francisco.) My 2.4 GHz signal is awful.
The remote is a nice addition, assuming the UI is good.
Using Chromecast with services like Netflix is sometimes pretty painful (Not always clear how to change the episode you're watching, if it's even possible. Unclear how to turn the dang thing off so it isn't just on some show, etc)
Chromecast is great, but it would be nice to have a somewhat standalone device to do everything, rather than needing a smartphone, computer, Plex server, etc.
The reason I replaced it was because of the purpose it was designed to serve and how I was using it. A Chromecast is a remote viewport, not generally a consumer (save for Chrome and a handful of mobile apps). Take, for example, when I used Plex. I'd have my machine as the Plex server, my phone as the Plex consumer / controller, and the Chromecast as the viewport. All three would be on a private network served up from my travel router, disconnected from the WAN (hotel internet paranoia). All three of my internet-connected devices were required to make this setup work.
edit
Just remembered the requirement that the LAN be connected to the internet to use a Chromecast. When I'm streaming from Plex, I don't need to be on the internet. Getting connected just so I could then use Plex felt like an unnecessary hurdle.
end edit
Contrast that with the Roku which is not only the viewport but also the consumer / controller. It freed up my phone to remain on the cellular network. I could pass out watching a movie and not have to worry about missing "important" late night notifications / emails.
The alternative was to stream my screen to the Chromecast, but I found that to have tons of lag / frame-skipping.
Admittedly, it's a very particular concern. <g>