Microsoft Access is a very low-end
database in terms of
scalability and storage capacity, but it is actually fairly good for what it does.
If you don't have the time, money, or need for a more reliable system and you have a small userbase with infrequent demands, Microsoft Access is easy to use (for a database) and very fast to develop on. Since it comes standard with Microsoft Office, it is also cheap to buy and already available to many Windows users.
Additionally, it is excellent as a system to help move data between two otherwise incompatible databases, such as Oracle and SQL Server, as it is often much more usable than the often unwieldy import/export tools that other databases provide.
Finally, personal experience has shown that Microsoft Access can be used as the database backend to a website with decent performance. I have written a website that runs off my personal computer via cable modem, that uses Apache Webserver to make CGI calls through Visual Basic compiled pages to an Access database. Surprisingly, this is adequate to take the current load of 5,000+ pageviews a day with no problems whatsoever. Yes, I could have written it with a more robust operating system, programming language, and database, but it was fast, required no learning, and was "free" (made of components already bundled onto the computer by the evil empire).