Ok, I'll bite.

Triples have traditionally been the best answer to cover a wide gear range, with close spacing in the steps between gears.

When bikes had 6 speed cassettes, a triple was a great answer to cover a wide range.

With the advent of more and more cogs on the back, compact cranksets with smaller rings, and 11 tooth rear cogs, the case for triples is becoming much more questionable.

With 6 cogs, and the smallest one being a 14, you just can't cover a range of say 122 gear inches to 32 gear inches, with a double crank, without huge gaps.

With 11 cogs, and a compact crank, no problem.