I think this is a good question in the OP

For myself, I feel like socionics can be a bit of a bridge that allows for commonality or transference of meaning, so in a general sense (or at "not very close psychological distance), being of the same quadra can smooth things over. It is particularly a problem when there is no common ground AND there is difficulty in terms of socioincs - but what I'm talking about here is more about actually conveying meaning or intention accurately, with understanding.

In terms of long lasting relations, I have some people who are outside of delta, but that's more because we are aligned in other ways, life goals, life paths, etc. I think that is more dominant, but I think socionics compatibility makes it a little easier to interpret whether or not someone is able to do that with you - to understand what they share with you.