It makes assembly code reverse engineering much harder by obfuscating names.
If you are sure some of public members are not to be accessed from outside, you may want to obfuscate them.
For exe executables you may consider the assemblies to be self-contained, and set obfuscation of all possible names very aggressively, including Public Members.Some Skater settings allow to generated names that will prevent recompilation.
Public members in dll libraries are advisedly reserved from obfuscation because they are intended to be used in external assembly code. Private and Public members names obfuscation scrambles names of classes, methods, variables, and other assembly members.

Only specified strings will be encrypted/obfuscated.
Since Strings can provide useful clues for anyone trying to reverse-engineer your code it makes sense to protect your string data from spying eyes. You have choice to apply a cryptography method for the string encryption. The string encryption function allows you to select literal values of string data type to be encrypted. However, for example, an attacker trying to break a licensing routine would first focus attention on Strings having to do with licensing to locate the appropriate spot of code. Also you may mark some specific strings to obfuscate. Skater can make this more difficult by encrypting the strings in your .NET assembly. You may select all strings to be encrypted. This is done by inserting a decryption routine into the assembly and calling the decryption code at runtime to return the original Strings.It will not prevent an absolute hacker from deciphering the conversion and seeing your data.