Safe to delete provided you don't need them and the services they provide. For instance, if you remove the "Camera" package, you won't have the benefits of a proper camera app if you don't install a third party one yourself (though there are some good third party camera apps like Camera Zoom FX for instance.) It's definitely safe to delete it -- your phone won't stop working or anything -- but without it or a replacement for it you have no proper camera app and the best you could do is try to save a picture from some other built-in thing if you don't replace it with something else.
So basically it just means it's safe to remove them if you know what you're doing.
Titanium Backup Pro can "freeze" apps effectively completely disabling them as if they were removed without actually physically removing them. When in doubt you can use it to test for lost functionality before actually removing things. Actually, I'm mostly just freezing on mine. The Samsung Galaxy S3 has tons of space even in the smaller 16GB model and I'm not convinced that even if I removed every single thing marked safe to delete I'd notice a huge difference in storage... (In fact, until I installed The Bard's Tale -- which uses something like 1.5 gigabytes of data -- I was going nuts throwing tons of stuff on there without running into that limit yet. Even then, all I had to do was move one video file off and I had enough space...) Removing built in packages will probably make so little difference as to just not be worth it. The free version won't freeze apps, but it can make a backup before actually deleting, which is still a lot safer than just removing. Some things can be just "disabled" in the settings under applications though which seems to be virtually the same thing as freezing.
Isn't that the phone app
