What are the pros and cons of website builders for a marketing site?

I'm an independent app developer looking to create a marketing web site for my app. I want it to be visually simple, minimal, responsive, superfast and be beautifully designed, like https://overcast.fm/ or https://thomas101.github.io/wmail/. It should make an excellent first impression to potential customers, rather than seeming like a run-of-the-mill site. Are drag-and-drop website builders like Weebly a good fit for this? The goal is to not put in more effort than necessary on the site, because most of my efforts should go into the app, not the site. If my app is a smashing success and, one year from now, I have to rebuild the site from scratch in code, that's not a problem. At this point, I don't want to spend too much time solving a problem I don't have, and may never have.