Are they objectively more important in the sense that the absence of one affects more than others? Sure.
But I think it's easier to find a baseline competent slip catcher than in the covers/gully who will be both a good ground fielder and catcher.
The marginal value of an exceptional slip catcher to take blinders is a bit exaggerated IMO because most here assume the alternative is an exceptionally bad 90s Pakistan slip, which is not the reality for most teams.
Like literally every single time you post you prove my point for me.
1. Gully is part of the cordon
2. Teams rake exceptional fielders from the slips and place them in the cordon when the show potential. Because it's more important. Harvey, Richards etc etc.
3. People get selected or keep said selections because they are slip specialists.
4. Austria's cordon in the India series was well above Pakistan's, Khawaja's drops cost them two games. When Smith finally got it together in that series he held multiple match winning blinders, especially in the final test. Catches Usman aren't taking. He had similar performances in the SL series.
Again, I know this is part of your master plan, but devaluing what guys like Waugh, Hooper, Kallis etc consistently did is stupid. Just one example, that famous '84 series that at the time sealed the WI as the greatest ever, Lloyd and Richardson contributed more to that team in the cordon than even with the bat. The catches they took were ridiculous.
Infact the hall mark for the tow best teams of the modern era, were their slip cordons and the catches and half chances taken. For SA, the team that succeeded Aus as the best in the world followed the same exact template.
Sometimes when you start I genuinely don't know if it's your biases or ignorance showing.