What’s the difference between DWARF and DWARF with dSYM file?

The difference is that in the case of DWARF with dSYM file your Archive app.xcarchive (for adHoc distribution) contains also dSYM file needed for reverse symbolication of your code in crash reports. In general, .xcarchive contains

dSyms
Products
info.plist

So if you need it for external analysis of crash reports under archiving you app for distribution you should use DWARF with dSYM file.