Yes, please let it continue its travels.
There are not many geocaches which can hold a TB this size, but it can often wait nearby. Anyway, there are some TBs which are just there to be discovered, such as cars or pets. This one would be quite a talking point at any geocaching event.
We had great fun helping this TB meet its 2016 goal of returning to the USA. It was photographed with some historic bricks (Windsor castle and Hampton Court palace). We have a X-ray of it at airport security. (It looked like a block of Semtex!)
It would be really nice if it could get to the last two continents. Antarctica will be hard - flights are very weight limited because they can not refuel there and have to make the return trip on one tank of fuel. Ships are not very frequent but there must be geocachers going. South America is easier - we would even consider a trip just to get it logged there.
So yes, for sure, please release it back into the wild. People wil get a lot of fun with it.