> Why in the world would you own bonds?

Because when every corp/muni bond folds - government issued bonds do not(and never have). Also, because they skyrocket in value during government-to-government conflict. Military action? 150% bond prices. It's a low risk instrument that turns into a winning lottery ticket for events such as.. North Korea launching a ballistic missile ~2 years ago, Donald Trump being accused of Russian collusion 3 years ago, and every military conflict ever.

Note, I'm not saying "govt bonds are great! buy them!"...I'm saying there are very old and valid reasons to own bonds of the government-backed variety.