Physical discs have a much higher bitrate than streaming. This means less compression, more detail in fast-moving scenes (like the blizzard), and a cleaner overall look.
* Technical Specs: Two-Disc UHD Combo Pack, UHD-66 Dual-Layer Disc / BD-50 Dual-Layer Disc, Region Free. * Video Resolution/Codec: High Def Digest Frozen 4K Blu-ray Review - AVForums frozen 1 4k