Is it okay to use a non mfi wall adapter on iphone

Is it okay to use a ETL certified wall adapter on my phone and it doesn’t say its mfi on the box

The brand is ihome and it’s 10 watts and i’m using the cable that came with the phone will it hurt my phone ?

also when i charge my phone with the wall adapter it takes a little more time to show that its charging than the charger im sharing currently between my ipad and phone with

is that normal?