cp is designed to copy data from one file to another. Block devices are represented as files, and cp won't be speed limited by block size.

dd is also designed to copy data from one file to another, in blocks, with optional conversion of the data (eg, from EBCDIC to ASCII), and with optional offsets/limits to copy regions of a file.

dd is not designed to copy raw block data, it is merely a different file copy tool.

You don't know what cp is for. cp is exactly for copying data from a file to another file -- and under Unix, devices are represented as files. Using cp for writing disk ISOs to an USB drive is proper use, not abuse.

dd is for transform-and-copy, so you're abusing dd when writing disk ISOs. The fact that most of the Internet is wrong doesn't make you any less wrong.