you have a lot of services who provide all infrastructure behind of a masternode. You just pay around 10-20 usd /month for it.
In DASH you have possibility to pay certain % to MN operator automatically. So one time set - and forget it. You just get rewards. No further communication is required.
That is, this service provides all the maintenance for running and maintaining the masternode? including all updates and reinstall wallet?
But this is related to saving your time and gives you the opportunity to make your activity trouble-free using automatic payment. But how does this provide an opportunity to receive passive income?
After setting up your masternode, you will wait for the rewards that will generated each time the shares has been distributed, it is a passive income as you will not do anything but to wait, there's allocated shares from each master node and after that you have all the power whether to hold or sell it right always to convert into a fiat value.