Even though it has pretty much the same meaning, i think they want us to differentiate between "Noi due" and "Noi entrambi"
We two are similar / the two of us are similar / us two are similar (slightly more colloquial/improper) / we are the two of us similar, etc. all these make sense
These are all fine except 'we are the two of us similar' which sounds odd in English
It might sound less odd if I put the parenthetical commas in: We are, the two of us, similar.
tutti a due = both. this is one of my favorites. I love to be able to use it in a sentence. On one happy occasion I got to ask a taxi driver if he could pick us both up from different locations.