There is a set of advantage for unlocking your Samsung Galaxy S6 phone. The prime advantages of the unlocking are the enhanced usability of the phone.
Freedom to choose- If you have the unlock Samsung Galaxy S6, then you can take whatever network carrier you want. Well, that gives you enough freedom to choose the best plan, discounts, and best coverage.
Relief from charges- It is always seen that people who travel a lot have to bear roaming charges for one province to another. However, unlocked Samsung Galaxy S6 can give them the leverage to take a local SIM card and avoid the unnecessary charges. Unlock codes for Samsung galaxy S6 can be provided by a particular unlocking service provider. The same can be applied to people who often travel abroad for long durations or settled in some other countries. The same stylish Samsung Galaxy S6 can be used with different network providers if the phone is unlocked. Once you’ve completed your contract on any carrier, you can (usually) get an unlock code from them. This allows you to use that phone on multiple carriers with the caveat that your phone may only work on certain carriers. Depending on the hardware, the rule of thumb is GSM will most likely work as a “world phone” as most carriers outside of the US operate on GSM-based networks. Phones specific to Verizon Wireless, Sprint, etc. use CDMA and cannot switch to AT&T or work overseas. Certain phones on any carrier touted as a “world phone” often have both CDMA and GSM capability built in. That being said, you specified the Z3, which is found at T-Mobile (possibly other carriers, just was my first find). T-Mobile is GSM and so is AT&T. If you got an unlocked Z3, it will work on AT&T as well, but one thing I have found recently is that the compatibility of the faster data networks might still be proprietary. So I don’t know for sure, but the Z3 will probably work on AT&T for phone calls and 3G, but might have issues with AT&T’s 4G LTE data, or may require rooting the phone and using a 3rd party room to get it completely working with it. There is no real “con” in unlocking your phone. It’s not like rooting it to where it might cause it to stop working or void a warranty. Hope that helps!
Another advantage can be that you can travel without any hassle. When you’re going overseas, you’re going to rack up massive charges on your service plan. That’s why you’ll usually find kiosks selling local prepaid sim cards in airports. Once you’ve got your phone unlocked, you can pop one of these babies in and you won’t have to worry about any unexpected charges. So, if you’re ready to unlock your phone, you could use Unlock Authority. This is a verified and legit service, which is important to note because there are a lot of sketchy services offering unlock codes. So use Unlock Authority to grab a code so you can use your phone without any restrictions.