Explain the problem as you see it
Some nodes you don't want to see when you are using either the search bar or when Tana is auto suggesting. For example, I might set up a supertag that is only going to be used to extend other supertags so I will not want to see that tag autosuggested (ex. a #project tag that won't be used but will extend several tags that will be like #internal project).
Another example is if you are using inline references for interstitial journaling, it is highly unlikely that you will want a line item in your interstitial journal to show up in any autosuggest.
Why is this a problem for you?
I have had many times where I am trying to create an inline reference, tag a node, or input criteria for a search node where i have only seen nodes I don't care about and can't find the nodes I do. It slows me down significantly.
Suggest a solution
Create an option to hide (i.e. never display) a node from search/autosuggest.