Many modern PHP applications no longer work according to the old model of «shared nothing», which does not preserve state between requests. In this regard Preload appeared in PHP 7.4, but while it does not work quite stably, using Roadrunner is a very good solution.
The last one, unfortunately, imposes some inconvenience on the familiar development process. Popular PHP frameworks (Laravel, Symfony) use the symfony/var-dumper component, which conflicts with Roadrunner executing from php-cli. If you try to use dd() or dump() function, you will see the following:
worker error: invalid data found in the buffer (possible echo)