On a support page, Google details the full list of 180 countries in which Bard is now available. This includes countries all over the globe, but very noticeably not any countries that are a part of the European Union. It’s a big absence from what is otherwise a global expansion for Google’s AI.
The reason why isn’t officially stated by Google, but it seems reasonable to believe that it’s related to GDPR. Just last month, Italy briefly banned ChatGPT over similar concerns that the AI couldn’t comply with the regulations. Google also slyly hints this might be the case saying that further Bard expansions will be made “consistent with local regulations.”
In other words, Bard probably does things that run afoul of the stricter privacy regulations in the EU. Make of that what you will.