DWR (definition hidden in OP) just stands for Durable Water Repellent, and it's the standard fabric tech used on all camping and cycling gear advertised as "breathable". A tight weave fabric (usually nylon) is coated with a water repellent solution. The weave of the fabric is supposedly designed such that vapor (evaporating sweat) can escape through the micropores, but droplets (rain) are too large and have too high a surface tension to pass through the pores/coating.

The advantages over a non-breathable garment are simple: You don't get all fouled up in your own sweat.
The disadvantages are less obvious:
- Over long exposure and heavy saturation, DWR will soak through. Eventually the wicking action of accumulated sweat inside and beaded water outside will allow 2-way permeability of the fabric.
- DWR is suceptible to dirt. Micro-abrasion of the coating wears down the effectivity.
- DWR is suceptible to detergents and laundering. Use a DWR-safe tech wash and delicate setting when laundering DWR garments.
- DWR is suceptible to abusive handling. Repeat crumpling of the fabric wears down the coating effectivity.

On the upside, you can re-coat DWR fabrics and usually renew them back to original functionality. Nikwax makes a great wash-in re-coating solution I've used on my hiking gear.
Spray on solutions too often contain silanizing compounds, which stink to high heaven and can cause allergic reactions in many people due to the suspending agents.
If I were to make a pair of "street pants" into water repellent ride gear, I'd look at a pair of tight-weave mid-weight pants (light denim or other canvas-like fabric) and use Filson's Oil Finish Wax (for reproofing their Tin Cloth field garments).