Is it safe to render the creditcard in my application

I'm currently adding stripe to my application. I think stripe form doesn't look that good, therefore I would like to beautify the form.

I found this gem https://rails-assets.org/#/components/card which does render the user input in a creditcard. I remember that a few months ago I watched a video where someone implemented this, but later deleted the card form, since it wasn't save to use with stripe.

I'm currently unaware why this shouldn't be save to use. Probably someone can help me out ?