If having two actors who look different with different eye color playing the same character doesn't bother you, great. Unfortunately it bothers me. For me, it's like seeing a character who's flying through the air and I can see the wires holding him up. It's like a giant neon flashing sign announcing that this is all fake and it takes me out of the story. But that's me.
You'd think the fact that you're watching it projected onto a flat screen, or that the characters have cameras pointing at them without being aware of it, or that there's music playing in the background without the characters noticing that either, or that a lot of them look and sound like actors you recognize from other roles, would be enough to announce that it's fake.
Just watching TV or movies at all, or watching a play, or reading a book, or experiencing fiction in any form, requires some suspension of disbelief. You always know that it's not real, but you choose to play along with the illusion. You exert your own imagination by choosing to ignore the evidence that it's illusory. Just like you did when you were a child and pretended your backyard was a jungle or an alien planet or whatever.