Fiverr for development is a race to the bottom and if you are US based, you'll be competing with people who are happy making a fraction of the hourly rate you need to feed yourself. I will say in the past I have used fiverr really successfully for some things, like translations, voiceovers, recordings etc. But I'd never try to sell development services there.
Now for the MAJOR negative. I used fiverr a few months back for an image editing/creation process (cause I absolutely suck at that) and my credit card through fiverr was compromised and I had to go through hell to fix it. I know it was fiverr because of two reasons, the card number was brand new and had never been used online and only used with one local vendor whom I have used for years. When the bank did the investigation they also blamed fiverr and took care of things for me, but it was super frustrating for me (thankfully the bank was really very helpful). I don't trust fiverr has a secure system anymore. The card wasn't just billed from fiverr but other third parties trying to purchase over $5k in electronics and even furniture.
When I posted about this other places, I found out many people in the past 6 months or so have reported similar issues after using fiverr. Dunno what is going on but I sure wouldn't trust my bank details (or credit card info) with them for sure.