Welcome to the Forum.
As for the 45-70 for the purposes that you mentioned, it wouldn't be my first choice. But to each their own. The ammo is a little pricey for paper punching unless you load your own (reloading is fun and rewarding and we have threads about that). As for home defense, the 45-70 is a little over kill.
However, I really like my lever guns and Marlin is as good as they come (especially if you find a used JM model). Personally, I would lean towards a .357, .44 mag. or a .45 LC for home defense because they hold 10 rounds, the ammo is less expensive and either is a good defense load. If you think that hunting is somewhere in your future, the 45-70 would be a good choice.
But, you did ask for opinions and ultimately the choice is yours. Let us know what you decide.
And again, welcome.