Interesting questions…
How it is better than Selenium IDE.?
For me the two key differences are
- Visual testing options with computer vision and even OCR (XClick,…). This is a bit like applitools.
- The XClick and XType commands work on truly every website and component. They are useful if the Selenium IDE like commands fail.
Other differences:
- You can mix browser automation and desktop automation e. g. to drag a file from the desktop to the browser.
- Supports canvas test automation
- Actively developed (vs. last Selenium IDE update was March 2020?)
- See also UI.Vision vs Selenium IDE
What it can not do:
- UIVision does not have code export.
Is it possible to execute the UI.Vision in CLI mode as Selenium IDE ?
Yes, UIvsion has a command line interface.
Is UI.Vision is open source so that if we willing to contribute is that is possible.
In Selenium IDE some commands like waitforcomponentstovisible/load are not at all working so we need to go with pause time not sure we will hit such an issue with UI.Vision also?
This is a perfect use case for the visual commands I mentioned above 
In this case I would use visualAssert | image_of_the_component.png.
See also Wait for Button and for second page load - #2 by Plankton or Wait for the logo to disappear