OT: I have not seen those recommenadtions, but they come with several disavantages. Let´s say you edit 4K video and need to output for delivery 4K, 1080p, 720p it would be a workflow disaster to change the sequence settings from 4K to 1080p, from 1080p to 720p for outputting three files. And then back again. Some effects/position/scale etc can easy be off making QC a nightmare. I will always recommend a 4K sequence if the source footage is 4K. Edit in one resolution, output to many in a convinient and efficient way. But yes, more room for positioning/zooming in 4K footage if the intended output is 1080p is possible when editing 4K footage in a 1080p timeline. So there are always exceptions! 🙂
To add to my last comment, it's recommended that the sequence resolution be set to the intended delivery size. That preserves the processing time for all the effects, graphics, and color adjustments added to the Sequence.
By @Ishan Y
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