Ammeters require heavy wiring, and manufacturers are cheap But, seriously, they will tell you an ammeter only shows charge or discharge, and doesn't show the condition of your battery, where a voltmeter will.
1940 Chevy 1/2 ton pickup "KC" A day without sunshine is like, well, ..... dark!
But, seriously, they will tell you an ammeter only shows charge or discharge, and doesn't show the condition of your battery, where a voltmeter will.