We're having problems here. I'll try and make it clearer
Electric pianos do exist. They are a real instrument. An electric piano is (and only is) an instrument where hammers hit a tuned piece of metal, creating a sound which is then processed/amplified with electricity.
You know how a lot of keyboards have an 'electric piano' voice (usually number 2 or 3)? That's where the keyboard is simulating the sound of an electric piano. It doesn't sound like a piano. It doesn't sound like a keyboard set to 'piano' mode. It is an entire instrument in its own right, just as an electric guitar differs from an acoustic or classical guitar.
You can't call a keyboard, trying to sound like a real piano, an electric piano. It doesn't sound like an electric piano. It isn't even trying to sound like an electric piano. People who make keyboards wouldn't even think of calling it an electric piano, because they know it's not, and it's not trying to be. They might call it a digital piano, but we'll get onto that later.
Now, I only got to Grade 6 on the piano so my opinion is clearly worth less than yours, but no, I wouldn't call a Yamaha Clavinova a piano. Also, I have never played a keyboard (or 'digital piano') that in any way accurately simulated the feel or response of playing a piano. But that isn't even the point. The goddamn point is, if a word means something, you can't call things that aren't what that word means, by that word. It's like calling a CD a tape cassette. Sure, they both might produce similar sounds, but a CD just isn't a cassette.
Also, can't these 'digital pianos' usually reproduce the sounds of other instruments, like harpsichords and pipe organs? Why don't you say "this is my pipe organ"?
I'm really surprised this debate has got this far, to be honest. I thought we pretty much had it wrapped up when I said my computer was a ukelele, but, clearly not.