It appears that practically every page load is causing this file to be re-written. For instance, the wp-login.php page calls create_compiled_config via this stacktrace:
/wp-content/plugins/w3-total-cache/lib/W3/Config.php:118
/wp-content/plugins/w3-total-cache/lib/W3/Config.php:40
/wp-content/plugins/w3-total-cache/inc/define.php:1418
/wp-content/plugins/w3-total-cache/lib/W3/Redirect.php:19
/wp-content/plugins/w3-total-cache/inc/define.php:1418
/wp-content/advanced-cache.php:29
/wp-settings.php:58
/wp-config.php:103
/wp-load.php:29
/wp-login.php:12
I don't particularly want to open permissions for every php file so that they can all rewrite the w3tc config file. I would just ignore it, but the side effects are bad. Under my host's config, the file gets created, but then it can't be written or unlinked afterwards, so it lingers...
On top of that, for a plugin that is performance oriented, rewriting the (compiled) config file on every load seems like a bad idea.