I don't think cabin crew will really notice this if they have any wit about them. Ryanair already operate the minimum cabin crew that the authorities allow so there is little chance of them losing out to a 'vending machine.'
The article seems to suggest that a cabin crew's role is focused solely on service and "making sure seatbelts are fastened." This is very much their secondary role and for the airline to go about focusing their role on service is not only incorrect but very insulting to the staff.
Typical Ryanair April fools and I must say, it isn't their best compared to previous years.