The term “quants” is used by different businesses in finance to refer to people of different quantitative skills. IB has its “quants”, but they’re working mostly on mathematically-unsophisticated spreadsheet models. At the other end of the spectrum, there’re “quants” who work in the fixed-income derivatives business who have PhDs in math, physics, or economics. At the height of that business, it wasn’t unusual to see some professors in academia became “quants” (even a few Nobel laureates were among them).
Hiring of people with advanced CS degrees is a relatively recent phenomenon, even though the founder of one of the major original quant hedge funds was a CS professor. As data become ever more critical, there will be more “quants” with CS PhDs (than PhDs in other quantitative disciplines) on Wall Street.