I believe setting a max payout will lead to less bot impact, in the short term, until bot authors adapt, that is.
At the moment, the UI only supports Decline Payout, apart from the default. But for certain types of posts, I've been trying out a max payout of 99¢.
It occurs to me, if this was a widespread practice, it might cause an issue to automated curation logic.
This is because, if the max payout is set small enough, curation rewards are practically the same outcome as Decline Payout (zero curation rewards), and thus yields no direct benefit for the curator.
Of course, it's pretty simple to do a work-around, but it requires resources and effort. This is because in order for a bot to know an author has set a max payout, the bot must request the full post or at least the related comment_options operation.
In other words, a bot cannot just stream posts and blindly vote. The practice of setting a max payout adds technical debt. Well written bots probably already gather more information, so this is just an additional condition.
Currently, Dr. Phil only looks for Decline Payout. Since the steemit.com UI doesn't offer additional options, there isn't much impact at the moment.
Technical Debt
The more hoops we make bots jump through, the better.
As these kinds of conditions continue to grow, bot maintainers must add logic and conditions to deal with them. Over time, depending on how well the logic is implemented, it will become more difficult to maintain.
Bot authors might not always document why a particular condition exists. Months or years later, this adds to the difficulty in maintaining the bot.
The upshot is that when the difficulty for maintaining bots gets higher, manual curation naturally gains the advantage over the long term.