It’s an excellent means of being tax efficient, paying for something without incurring interest, and keeping fit and healthy.
I get some of the complaints re: self employed, but then again, Class 2+4 NICs are lower rates than class 1, and are based on profit rather than income. They also have their self assessment and their tax deductible expenses.
Equally, our taxation system has many cliff edges and biases so I don’t think attacking fellow cyclists is the way to go. Take child benefit as an example – a family with one adult working, with an income over £50k starts to lose it, with it disappearing entirely at £60k. A family with two people working, earning £49k each, get to keep it all.
CycleScheme usually allows you to pay fair market value after 4 years, at 7% of package price.