More cameras on a phone is great and all, but in most cases, the only app that can use them is the system camera. Samsung's Galaxy S10+ has five separate cameras, two on the front (one regular, one depth-sensing) and three on the back (one regular, one wide-angle, and one telephoto), and the S10 has the same setup minus the front depth sensor. As part of a recent software update, apps on the S10 can now access more than just the regular front and back cameras.
The latest system update for the S10 series includes a new 'ultra-wide SDK' for third-party applications. This means that once an app is updated to work with the SDK, it can use the rear wide-angle camera on the S10. The SDK also gives apps the option of using the non-cropped view for selfies, which has been an annoyance for many S10 owners.
It might be a while before most mainstream applications are updated to support the new software functionality, but at least the option is there now.