I think most recent 4KTVs do a solid job with scaling and latency, though. Just looking through RTINGS data, even most mid to lower-end TVs produce the exact same latency in both 4K and 1080p modes. It's quite rare that 1080p exhibits more latency over 4K.I'm not arguing that the C8 specifically isn't fine. Just because you can list one display that scales up well doesn't mean that most of them do. A lot of displays are absolutely terrible at rendering non native resolutions.
Either way, if you're serious about perfection then you should own the best displays as well! Even if you can't afford that, the lower tier displays handle 1080p beautifully so it's a non-issue.
Do you have a specific TV in mind then? I feel like you must have encountered a shitty 4K TV with a poor scaler and high latency to make that comment.