The 2″ focuser is an important part of the optical tube. As you might guess, it will work with larger eyepieces that have wider field views. This is a great advantage with deep space objects, and will overall provide a better viewing experience. And it is made of mostly metal instead of plastic.
The red dot finder is the simplest finder you can get. It just projects a red dot on a screen. It is a matter of preference, but I think it is much better than any scope type finder. It does its job properly, is easy to use, and cheap.
The diagonal that comes with the telescope is slightly disappointing. It is a plastic amici. It lowers the image quality by creating a spike in the middle and lowering the brightness. It also adds slight astigmatism. It would be the first accessory I would change with a better one.
The 2x Barlow is unnecessary. It only provides a decent image with the 26mm eyepiece by providing a 46x power. But for higher magnification images you can already use the 9mm eyepiece.
Overall there is nothing surprising about the accessories other than the 2″ focuser. They are of below-average quality and will serve you well in the beginning.