Hi there,I have a Roku and a Chromecast as well and find the Roku to be superior in pretty much every way.If you want to use your phone as a remote you can do that with either device. However if you want to just lay back and not deal with a phone and just have a little simple remote to browse channels and whatnot then you have to get the Roku for that since the Chromecast requires your phone.
Here is how it works if you want to use your phone as a remote with either device. Go into an app, for example YouTube and start playing a video. If the app supports casting it will show a cast button
. Clicking this will pop up a window displaying a list of devices you can try to play the video on. You can choose Chromecast here or you can choose Roku here and any other devices and your video will start the app up on that device and start playing.
You can also cast to the Chromecast from a Chromium based browser like Chrome or Vivaldi if you want to cast your browser or even your entire desktop. For the Roku you can enable screen mirroring
and you can cast your Windows screen to it that way.
If you have your HDMI-CEC setup you might even be able to pause it and unpause and even stop it with your TV remote on the Chromecast. If you have a Roku you can do that with the Roku remote as well as fast-forward, rewind, sometimes do other things like get info or sometimes channels have additional functionality built into them. Some are actually even games like Angry Birds. Plus I believe the remote has a headphone jack and even a mic for voice searches. It's possible it might also be able to turn your TV on and off and adjust the volume with the Roku remote.
Also, managing settings on the Roku is much simpler than the Chromecast for me. For the Chromecast we have to use a Google Home app to manage it's settings and I always find it confusing where to find the settings I want for some reason. Recently they seem to have added a setting to change the slideshow speed which was defaulted to 1 second so the Chromecast was constantly using up all the bandwidth downloading new images every second. Took me awhile to figure out that was the issue and I don't think my roommate has even found his settings yet for his Chromecast to make sure it isn't using even more bandwidth.
There are also other ways to stream videos too. For example there are other types of streaming boxes out there as well and some may have similar features and many have their own remotes although some of the remotes aren't so simple and easy to use as the Roku remote. It's also possible to set a computer up to behave similarly since that's really what all of this is anyway is a bunch of computers playing videos. You could probably even set up your own with a Raspberry Pi or something if you were real ambitious and wanted to go the DIY route.The only major issue I seem to be currently having with both devices is watching Twitch on them. If I want to watch it on the Chromecast I have to cast from my computer or use a 3rd party website to do it properly because the Android Twitch app is horrible and will use all my phone's resources for some reason and render it almost completely unusable until I close Twitch. As for the Roku, the official Twitch app seems to have been abandoned. The unofficial one was abandoned because the official one came along but now the official one is abandoned. So I found another one called Twitched but now it seems to have been shut down and isn't usable anymore which is pretty sad considering I paid for it. I'm not sure what's going on but it makes me wonder if Amazon are trying to force me to buy a Firestick which I won't do.Anyway, I think that's about enough rambling for now. Best of luck!It's Waffle Time!