If all you want to do is play bass and lead lines, the bassstation is good (I have one). If you want to do chords, then obviously not (I also have a roland DI61 and blofeld). When I play live I use an iPad connected to a mcmillen 12 step, where I play chords (with my feet) for backing stuff), and sometime use my Yamaha Reface DX to play other lines on when we need keys. For bass, I always use a bass though, and if I want a synth bass, I use a bass with a synth pedal.
If you have an iPad already, then what would give you the most flexability at the cheapest cost is a cheap master keyboard (and it can be small, the bassstation doesn't have many keys) and connect that to the iPad (they almost all have USB as well as midi, and they will connect with the apple USB connector).
something like the G4M one: https://www.gear4music.com/Keyboards-and-Pianos/SubZero-CommandKey25-Universal-MIDI-Controller/221X
means you can connect to something like the Moog Model D app (or model 15 if you are feeling brave), which gives you the same sounds you would get from a real model D, but 2.5k cheaper.
That will give the biggest scope of what you can play and maybe that will let you know which way you want to go.