Thanks! Yeah Conor mentioned that to me; I think the real benefit (at least personally for me) would be not being able to buy pre-made matching pairs of tokens,

Thanks! Yeah Conor mentioned that to me; I think the real benefit (at least personally for me) would be not being able to buy pre-made matching pairs of tokens, but being able to easily write my own key material plus the counter boost value. You know, yubikeys do have this functionality for OTP: their utility allows to program OTP keys. I actually expected the same for u2f, but alas.