It's up to you really - it's not compulsory but like just about all other cookers (AGAs with external oven venting excepted) the cooking smells vent from the ovens to the room, along with anything from the hotplates (and induction hob) so if you want to exhaust this to outside then you'll need to fit an extractor over the cooker.
There's no chimney or flue to worry about with the Everhot - so no need to avoid a pipe when choosing your extractor, and no need to worry that it'll upset the 'combustion' (or burner) of the cooker since there isn't one to be affected! (This can be a very important safety issue for any flued appliance in the same room as an extractor.
A small point to note - the Everhot's lid, when lifted up, is 1530mm above floor level. A clearance is needed for 'finger room' so any extractor, feature or canopy needs to be above this height (we recommend starting at at least 1650mm above floor level).