My partner and I are similar to you. We couldn't care less. I proposed to her, she said yes, we're happy with the way things are, nothing needed to change.
However. Legally speaking, when you get married, you are considered as a single legal entity in many things including court/law enforcement/taxes.
A person cannot be compelled to bear witness to their partners actions in court, in the USA, that's the fifth amendment, in Canada, it's section 11(c) of the charter of rights and freedoms. The basic concept being that you have the right to remain silent (and not incriminate yourself).
While I don't plan on doing any crime or anything.... That's a nice perk.
Also, she hates doing her taxes, so when we're married, I can do taxes for both of us.
There's very few perks here and bluntly, it's not worth the cost...
We're going to elope and just throw a "reception" (party) afterwards.
We wanted to do it this year on our anniversary, which was about a month ago now, but there was too much going on financially that even throwing a modest party with the budget constraints was going to create problems. We both had job disruptions in the last months of 2024, and things have just been a bit to hard financially to really bother.
We're starting to save for next year already. Planning shall begin soon.