It looks like taxes increase and any kind of post-life planning can be done with a few legal filings rather than getting married. Is there any real benefit? It kinda seems like it’s just a way to trap people in relationships, probably traditionally, the woman.
It’s generally intended only as a protection against self incrimination. If prosecutors want to force your testimony, they can grant you limited immunity from prosecution and you can be compelled to testify. Of course it gets way more complicated than that, and I’m not a lawyer.