I am interested in what the LTE Series 3 watch can do that the GPS Series 3 cannot besides phone calls. If you have nto enabled LTE, is there any other advantage?
Your question is hard to parse, I think because of typos. However, I think you are asking what you can do with an activated cellular Series 3 that you cannot do if you have not activated cellular, or are using a GPS only Series 3.
If so, see
https://www.imore.com/apple-watch-series-3-cellular-vs-gps-only-whats-difference
The Series 3's LTE coverage lets you do anything solo on the Apple Watch that you can do when tied to your iPhone's data. That includes placing calls, receiving messages, using Siri, navigating via Maps, playing with third-party apps, and just about anything else.
So, it depends on whether your phone is with you or not; it depends on whether you have a WiFi connection or not.
If you do not have your phone with you, and are not connected to WiFi, the cellular watch with cellular enabled can do those things listed above. With a GPS only watch, or with the cellular not activated on the watch, without a phone or WiFi connection, you can do workouts, play music that is previously stored on the watch, see what time it is, see what information was stored on the watch when you last accessed it. If you have previously set up Apple Pay on the watch, you can pay for things with Apple Pay. (You don't need a network connection to pay for things with Apple Pay.) That's about all I can think of.
If you have your phone with you, there isn't much difference. If your watch is connected to a previously known WiFi access point (for some reason, such as you are at home connected to your own WiFi but left your phone at work by mistake), it also isn't much different.