Here are a few channels that I watch ofen that always upload in 4k. This is not a niche for serious youtube channels:

https://www.youtube.com/channel/UCsn6cjffsvyOZCZxvGoJxGg

https://www.youtube.com/channel/UCHnyfMqiRRG1u-2MsSQLbXA

https://www.youtube.com/channel/UCSpFnDQr88xCZ80N-X7t0nQ

https://www.youtube.com/channel/UCXuqSBlHAE6Xw-yeJA0Tunw

Besides even at 1080p the difference in how much battery it saves is astounding. With acceleration your CPU is just idling while without it has to work quite hard.