Which is the best filematch to use in htaccess?

For example: would match most common Internet graphics formats. <FilesMatch> is preferred, however. Note that unlike <directory> and <location> sections, <Files> sections can be used inside .htaccess files.
Indeed, when to use filesmatch instead of files in htaccess?
NOTE: FilesMatch should be used instead of Files when dealing with multiple files. <FilesMatch> Directive Description: Contains directives that apply to regular-expression matched filenames Syntax: <FilesMatch regex> ... </FilesMatch> Context: server config, virtual host, directory, .htaccess
Consequently, what do you put in a.htaccess file? In general, .htaccess files use the same syntax as the main configuration files. What you can put in these files is determined by the AllowOverride directive. This directive specifies, in categories, what directives will be honored if they are found in a .htaccess file.
One may also ask, why does Apache search for a.htaccess file?
Unlike the main server configuration files like httpd.conf, Htaccess files are read on every request therefore changes in these files take immediate effect. Apache searches all directories and subdirectories that are htaccess-enabled for an .htaccess file which results in performance loss due to file accesses.
Just so, what happens if you mess with your.htaccess file?
Note: messing around in your .htaccess file is a great way to bring your site down. Always, always, always make sure you download a copy of your working .htaccess file before you change anything in the file. Until recently, I used the recommended settings GTmetrix prescribes on their site.