Typing braces is basically a gesture. You hold the shift key with left pinky, and roll right ring finger pinky over open and close brace, then tap back arrow and return to get you inside the block. End is three distinct key presses.

Also braces have a nice symmetry, which is also convenient for parsers and tooling to count opens and closes.

I also think "end" is just more visually noisy. Braces are a symbol, so it's easy to filter them out when you're looking at code, but a trail of "end"s takes up more real-estate than is semantically justified.