MacOS Laravel Valet increase memory_limit

I found a solution but I didn't understand why it works, but not what I did before. If anyone has an explanation, I'm interested.

I edit /usr/local/etc/php/7.4/php-fpm.d/valet-fpm.conf and replace following line php_admin_value[memory_limit] = 128M
With this line
php_admin_value[memory_limit] = 256M

Then I run the following command:

valet restart
brew services restart [email protected]

With just one of these two commands it doesn't work.
However valet restart is supposed to restart php, right?