How does BTT "Launch Apps" under the hood?

Discussion & Questions
1

Very simple use-case: bind right alt + s to Launch Slack.app

I've tried a number of alternatives such as Karabiner Elements, Hammerspoon and SKHD to bind the said trigger execute the open /Application/Slack.app on terminal. But it seems that BTT launches the apps noticeably quickly! So, I was curious to know how BTT handles launching apps the hood?
Or is it because of the Process Priority Helper Tool?

2

It's always going to be faster to launch an app with the native system API because when you use a script in Terminal a whole bunch of things need to happen:

  1. Terminal.app opens.
  2. It then opens a session.
  3. It starts a new process to parse and execute the script file.
  4. The script then calls the "open" utility, which finally uses a system API to open the app.

All those steps take time.