True, a lot of it depends on personal preference, too. I think the idea is to not worry about understanding 100%. Even just 70% could be fine! Or just the gist or emotion of the text could be enough.
Will you learn something? Yes probably, but will it be time and effort efficient? Not even slightly!
At 80-95% it can be productive if you're putting forth a lot of effort, but comprehensible input assumes comprehension above 95% for passive learning of materials.
To demonstrate what different (reading in this case) comprehension levels will get you take a look at this[1].
[1] https://www.sinosplice.com/life/archives/2016/08/25/what-80-...