When a beta SE gets closed, a data dump can be downloaded for a few days right after, then it's not possible to have access to the dump. It's annoying for several reasons:
- People who took part in the beta SE might want their data back and might miss the time window where they could download the dump;
- People who didn't take part in it could still be interested to read some Q&A on the site's topic;
- New beta SEs that have some overlapping interest with the closed SE could benefit from having access to the Q&A (understanding why it closed, what pitfalls they should avoid, and potentially copy the most interesting Q&A instead of starting from scratch);
- As a general principle, it's not great to remove user content.