No, unless a file needs to, then a permission lower will be safer, like the owner has 100% access or in your case, the server which can create, read and write.
The users, as in your case, the scripts, have access to read / write but not create.
Others, or in your case, the visitors to your site, have read only access.
A file with a permission of
0644 will be readable, writable by the scripts and the server but if the directory was listed, it would be invisible.
In certain circumstances, this is helpful in adding some security to files AND FOLDERS as you apply that setting to a folder, it means anything in it, including the folder is invisible to anyone but the scripts and server.
SO USE THIS WISELY as you can run in to problems very quickly if you apply the wrong permission in the wrong way and you could lock yourself out of your site root and the hosting company will have to reset you and that might set you back a fair bit of billing as thats
open season on people bricking their accounts.
YOU HAVE BEEN WARNED.