The underlying mechanisms are somewhat different, and this explains why SBD interest appears in your wallet and SP interest/antidilution does not.
SBD interest is paid directly to each user, so it shows up as a payment in your wallet. SP antidilution is paid (each block) to a single fund called the vesting fund, in which SP holders own shares called VESTS. Your VESTS are worth more STEEM every time these payment are made, but the number of VESTS you hold stays the same. That is, no individual payments are made to each user, so nothing shows up in your wallet.
Alternatively if the payment did show up in your wallet every three seconds, that would be a LOT of clutter!
Got it, thanks.
Regardless of the underlying mechanism, I still think something could be done to make the SP earned more clear to users. Perhaps a "daily SP earned" category or something of that nature.
Agree with you.