Does the American army still use those old civil war attires to this day for ceremonial purposes? ?

I saw Revolutionary War uniforms but no Civil War uniforms in the video.  The other ceremonial uniforms I saw were the current Army Service uniforms.

https://www.army.mil/uniforms/

Yes. They also wear ceremonial Revolutionary War uniforms too....the key work is ceremonial. 

That is not Civil War attire.

None of the uniforms in this video are from the Civil War. The clip you refer to is of the Old Guard Fife and Drum Corps in late-1700s uniforms (Civil War happened in the mid-1800s and the uniforms look nothing like this). Also featured in the video are the U.S. Army band in its current dress uniform and various soldiers in the current Army blue service uniform. There is also historic footage of soldiers in the WWI doughboy type uniform and WWII era uniforms. The Army as well as military heritage groups sometimes demonstrate various historic uniforms, including those from the Civil War, at parades or functions.

? -   There are actors who are still obsessed with The Civil War.   That was probably who you saw.   Sometimes, they even reenact battles of The Civil War - NOT with real bullets, of course.