It is not similar to staking via stakepool where you have complete control of your funds.
It's absolutely similar to staking via stakepool, because I register every Evolution user in the stake pool automatically (import pubkeyaddress, script etc). So yep, I never announced this, because I don't want to confuse users and I'm trying to simplify their life as much as possible, but every Evolution user has his own already configured account in the stake pool and I can give you full access to it (login is your email and very long random password I generate for each user; write me to
info@dcrstats.com if for some reason you want to login also to your stake pool account).
So, Evolution is Stakepool on steroids

You have 100% features and control like in the any stake pool + full automatization of the process, cool web interface, mobile app, stats and more coming soon.
The only difference is that to allow this automatization (what is one of the main goals of the project) the platform should control private keys to sign new ticket purchase transactions. But that is how any crypto exchange work, I'm not very happy with this approach as well, but that is what we have for now in crypto world. If the project will be popular enough, later I will start thinking about even more secure solution, something like 2 of 3 multisigs, so eg: you can sign purchase transactions from your mobile device, which should be online 24/7. But at this stage Decred software is not yet ready for such complex solutions.