Why does the program require a reboot after installation?

Question

Antivirus

Just installed a program for screen recording and video editing - Camtasia is called. I was confused that the installer of this program demanded that I close my browser, and when the program was installed, it wrote that I must restart the computer in order for the program to start. On the one hand, I need to record a master class at 18:00 today, and on the other hand, I'm afraid that the program can pierce the computer's protection.
Questions:
1) Why did the installer need me to close the browser?
2) Why does he want me to restart the computer?
3) How suspicious and dangerous are these requests for such a program?
4) If it is dangerous, will removal now help? I have not yet rebooted and did not run this program.

--- update:
I ran the installer on virustotal: it says undetected everywhere, except:

5) what does this mean?

Answer 1

If you gave the installer admin rights to install, then it's too late to drink Borjomi, he has already done what he wanted. It was necessary to immediately drive to VirusTotal.
A reboot is usually required to install services/drivers.
Since the program is intended for screen recording, in theory it can install a filter driver to intercept images displayed on the screen. Or, alternatively, to create a "virtual webcam" that displays the captured content.