That depends. First and foremost, it's a secure behaviour to only give yourself administrator rights (e.g. via sudo) when absolutely necessary. Also, if you happen to change the file's owner or permissions by accident in a way that the normal user can't access them anymore, it can cause further problems.
In short, by training yourself to use sudo only when necessary you avoid future problems and, at worst, security holes.
In your particular case, mere editing an existing file shouldn't make you any trouble, but if the file doesn't exist, you'll create it with the owner root instead of pi. Because a new file will be created with only write permissions for the owner, any application like an emulator that's run by pi wouldn't be able to write to this file afterwards.
Again, that may or may not be a problem depending on the file, but avoiding to use sudo will negate this uncertainty alltogether.
