I've met many penpals around the world here. We talk about our cultures, school systems, books, etc. It is amazing when you wake up and notice a letter from far away just coming to you.
I decided to join this site because of boredom and the pandemic. Its my first penpal experience and its been really fun so far getting to know people from different places around the world. The only downside is not everyone replies as fast. But going on the site everyday or every once in a while helps to find someone compatible you can talk to and make friends.
So far I have only had a good experience, the interface is easy to use and I would like to emphasize that the security of the correspondents is handled very well.
I do feel like GPP is the safest site for such things as giving out your addresses and meeting international friends. The "no-spam" policy and filters for friend searching helps you find reliable people.