4k input signal - On-camera monitor

[Alessandro]

Hello. Im' looking for a 5" on-camera monitor and I hesitate between IKAN's  DH5 and DH5e versions.

It's exactly the same monitor, however the E version also support 4k input signal and costs almost 100 euro more.

I was wondering if I really need the 4k support (surely not now, as I shoot mainly with a 5d2, but I'm planning to change my camera - maybe with a GH5)?

Does all 4k capable cameras can downscale the output to 1080p or in the next future monitors limited to 1080p input will be useless?

Thanks