It sounds like you're new to both React Native and the JavaScript ecosystem. I can imagine this being very frustrating for someone regardless of their general programming chops. I happen to be on a React Native project at work right now. Hopefully I can provide a viewpoint that is helpful and give direct answers to some of your questions.
One thing that would be helpful to understand that's missing from the OP, what are you building?
> However, seeing the differences between react and react native, this seems overstated.
I'm actually not sure which specific differences you're referring to. Perhaps you can clarify?
> It was recommended to use javascript and react/react native so I only needed to program once.
It's possible to use RN to build an application which runs on both Android and iOS from a single code base. This is possible with a few other environments but none are (IMO) quite as good at affording for a truly native look and feel including dropping down into native code when necessary.
Building a really great app is still a grind on execution and perfecting small details is a chore. The standards of quality in the mobile app world are high which leads to average users having higher standards than they might with desktop or web applications.
> What were the other benefits?
For people who enjoy working in JavaScript, the fact that you can write native applications using mostly JS is a benefit.
Some products benefit from being able to share code between a web product and a RN application is a big boost in productivity. I've personally saved hundreds of hours leveraging this. It's not a 1:1 swap but it's close enough to lower the mental burden compared to creating something from scratch.
> I thought there was already built components/libraries I could drop in for data management.
There are lots of data management libraries for React. Most can be used in a RN app. Maybe the community resources section of the React documentation will be helpful: https://reactjs.org/community/model-management.html
I can provide specific recommendations if you can describe specific needs. Like most ecosystems deciding which tool to use in which situation is a skill which builds up with experience.
One thing that would be helpful to understand that's missing from the OP, what are you building?
> However, seeing the differences between react and react native, this seems overstated.
I'm actually not sure which specific differences you're referring to. Perhaps you can clarify?
> It was recommended to use javascript and react/react native so I only needed to program once.
It's possible to use RN to build an application which runs on both Android and iOS from a single code base. This is possible with a few other environments but none are (IMO) quite as good at affording for a truly native look and feel including dropping down into native code when necessary.
Building a really great app is still a grind on execution and perfecting small details is a chore. The standards of quality in the mobile app world are high which leads to average users having higher standards than they might with desktop or web applications.
> What were the other benefits?
For people who enjoy working in JavaScript, the fact that you can write native applications using mostly JS is a benefit.
Some products benefit from being able to share code between a web product and a RN application is a big boost in productivity. I've personally saved hundreds of hours leveraging this. It's not a 1:1 swap but it's close enough to lower the mental burden compared to creating something from scratch.
> I thought there was already built components/libraries I could drop in for data management.
There are lots of data management libraries for React. Most can be used in a RN app. Maybe the community resources section of the React documentation will be helpful: https://reactjs.org/community/model-management.html
I can provide specific recommendations if you can describe specific needs. Like most ecosystems deciding which tool to use in which situation is a skill which builds up with experience.