Maybe some thoughts for new keyboard owners, who are thinking about buying (first) foot pedal...
If you're not sure what to buy, then you need a sustain (switch) pedal! There are more than 80 functions that can be assigned to foot pedal (Reference manual p.112) and over 95% of them can be used with sustain/switch pedal. Even further: if you're considering to buy additional foot pedal, it's probably sustain/switch pedal again.
About expression pedals.. Yes, it's tempting to be able to influence voice volume, glide/portamento, etc. while playing. But unless you're quite experienced musician, you will soon realize, that you're not using this feature as much you thought you would -at least that's my experience. The thing is, expression effects only make sense for certain instruments (voices). For example, volume expression is mostly used for organ playing. Here's an famous example of proper volume expression usage:
https://youtu.be/50xx1_CbJTIAs I mentioned in previous post, expression pedal (FC7) can be used "as switch", but is less practical for that purpose -and much too expensive to be used that way.
Bogdan