Because Steem auto doesn't have that functionality.

I will now set a delayed upvote to your comment with @rewarding so you can see it work. Rewarding will upvote the above comment 14 minutes after creation.

But only that comment and nothing else of yours.

Steemauto doesn't do evergreen rewards comments either.

$rewarding 45% 14min

It does make a difference do of you need to remember to return in 12 minutes. And for larger stakeholders the waste of curation share is ridiculously large if they vote within first 5 minutes.