If she likes the autos, let her have the autos

You could always order one manual battery for her to try and then let her decide definitively which she likes better. Both options have their benefits and it all comes down to personal preference
I'm with you on the reliability factor and, even more important to me, I like the ability to activate/deactivate the battery whenever I want. With some carto types I am prone to do two or three shorter activations during a single long draw (in some cases this is how I get the most satisfying hit from them), which I couldn't do with an auto. But that's just me, not everybody vapes the way I do