Hi, English isn’t my mother tongue so I was asking myself that question since I first encounted a w/… Back then I was like: “What tf does ‘w slash’ stand for?” And when I found out I was like “How, why, and is it any intuitive?” But I never dared to ask that until now
The ampersand (&) was so commonly used that for a while it was taught as a letter. British schoolkids in the mid- to late-19th century would include it as the 27th letter on writing work and needlework samplers, usually after “z”.
There’s some discussion that the Alphabet Song ends with “w, x, y & z” specifically to include it.