You can move blockchain files between your own Bitcoin installations, but they cannot be trusted if obtained from anonymous sources, as anything could be inserted without verification. Importation of the bootstrap file verifies the block contents the same way downloading it normally would.
In addition to this, the only other benefit you'd get from cloning the bitcoin directory is the chainstate folder, which is normally built as the blockchain downloads or is imported and verifies. Aside from that, the wallet file obviously can't be copied, the config file is generally different by machine if used at all, and the peers file is quickly and silently rebuilt so it doesn't really matter.
