Is there any considerations for not putting php scripts in tmpfs?

Hi php-general, sorry if it is a wrong lists for this question. I have read many articles/messages about using tmpfs store temp files, for example, php session data, smarty compied templates and so on. An obvious reason for that is: it doesn't matter about data loss caused by machine restart/poweroff. since it is not that difficult to restore files on a tmpfs from a disk-based dir when machine boot up. so may i put all my php scripts on a tmpfs to speed it up? would that cause other issues? thanks for your advices.