是否有充分的理由将相关数据集拆分为不同的SQL数据库而不仅仅是表格？

This question is motivated by a recent update to some business software a friend of mine is using. Their architecture was based on Access databases until now, which was awfully slow. They had split their datasets into multiple mdb files (sales.mdb, products.mdb, stock.mdb, ...). They are now moving on to SQL Server Express and keeping this structure. Instead of using a table for each of these datasets, they created different databases on the same instance of SQL Server 2008 Express.This question is motivated by a recent update t