Yes, the $20 optics are fine for fun at the range. However, in the video you posted, we can see that it's not waterproof like the MFR said. Water in electronics will eventually ruin them.

Also, the biggest difference is battery life. The Trijicon, Aimpoint and PA all have a 50K battery life. If the gun will be used for self-defense, you don't want to have to turn the optic on, it needs to be on already. With a 50K battery life, it can just be left on all the time. You can't do that with the $20 red dot.

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