There is no single answer to OP's question. While the utility of "open" tickets has largely gone away, on some routes and in some fare buckets, it may be worthwhile. In other situations, it may not. The only way to come to an answer for any particular situation is to check it out.

Certainly carriers do issue full YY tickets and there are sometimes reasons for those which go beyond immigration requirements. But, these days, it is most often far better to book the return ticket, fly the first segment and then pay the change fee for the second when you know your plans better.