Can use execute a binary from memory opposed to from a disk?

[Siddhartha]

What would be the point of ecryption then?

Encryption is used to protect data. Data unlike machine code contained by an executable is something that never gets executed. This is why your requirement to execute an encrypted file is not the norm.

(If I may I ask - why do you wish to do this?)

All someone would have to do is take the extra, tiny step, of locating the temp file and then reading it all decrypted.

That's right.

Which makes my question all the more important - what is in an executable that demands the same to be encrypted?