I would have expected AppThemes to have exerted the effort to make the Stripe payment page look more presentable and professional, rather than spartan. I'm not complaining, just pointing out that it could have been better.
Anyway, if you're a coder yourself, it's actually quite easy to make changes to the plugin's look and feel to match your site. I made some changes to the plugin's stripe-form.php and style.css files.
I'm just sharing here how I modified mine, and what my Stripe payment page looks like. Hopefully, it will inspire other users to come up with their own ideas and modifications. (Yes, I'm aware that I need to put my changes back in every time Stripe gets up-versioned. I'll deal with it.)