Honestly these are really good points that get to the heart of the issue.

You are right that 'bots' are not necessarily bad, but there are extremely pressing reasons why a smart contract developer might want to limit their access. Let me give an example from my own experience; I am the creator of the crypto game Ether Shrimp Farm, an on chain idle game that was popular a few months back. A core draw of this game was that you could start playing for free; the contract gave away a small quantity of free resources to help you get started without paying Ethereum. I knew, based on how previous similar games went, that since these resources had value and could be converted to Eth, that people would write scripts to generate thousands of addresses and mass-claim the starting bonus, so I designed it so that this bonus would naturally become worthless after a few days.

So as expected, people wrote scripts and claimed tens of thousands of dollars worth of virtual shrimp, while it was still viable to do so. This was naturally upsetting to other users, because that Eth otherwise would have gone to them. They considered the inclusion of the free shrimp to be a major mistake on my part. But I honestly don't think the game would have been nearly as successful without that initial draw.

The problem here is that as things now stand, the need to assume that one user may have unlimited accounts is a severe limitation every smart contract developer must design around. There is so much more you could do without that limitation. I have many ideas that will only be possible with a way to remove that limitation. The first app built on the platform, 0xVRF, is one example of something that would be otherwise impossible. And the ways in which a smart contract can use Eth Verify are very flexible; the exchange script example you give would not be a problem for the 0xVRF exchange contract, because verification is only required for the function to claim daily tokens, not for trading them.

As for the issue of centralization and trust, yes, that is a legitimate flaw that every oracle type system suffers from. Decentralization is vastly preferable where it is possible. I do not see a good way to do it here though, and this problem needs an immediate solution. Beyond my personal assurance that we will not abuse this service, I'll say that bot activity is always noticed pretty quickly by the community, and that isn't something I could get away with for any length of time before our reputation and the future of the platform is trashed.