Got mini when I thought it's more portable and I would carry it out. The truth is I still rarely take the iPad out of the house and continue to use iPhone all the time as it is more convenient.
If iPad is mostly for home, and you have the 4.7" or 5.5" iPhone, iPad Air is good enough (iPad Air 2 is last year's tech, wait for iPad Air 3 if you can)
I would even suggest that for home use (except for lying in bed, which iPhone is actually more ideal than even mini, and Air is still not as comfortable), iPad Pro may be the best for media consumption and reading.
Here's my suggestions:
1. if you have iPhone 5S, and want a bigger device to carry on your backpack outside of your home. Mini 4 is very nice (especially with LTE, tethering on a regular basis is a hassle)
2. if you have iPhone 6/6+/6S/6S+, hold onto your iPad Air and evaluate iPad Pro or wait for iPad Air 3 for home use