Why should I roll the meat in flour for a ragout
Flour is a thickening agent, plain and simple. However adding it without cooking it first can lead to your dish having a raw flour taste, and you can get blobs of flour in it, so I would ignore the recipes which say coat with flour without cooking it first, or use cornstarch (cornflour) instead. 

Alternatively you can make a roux with flour in a separate pan and add it in later. This is simply mixing equal weights of flour and butter and cooking it in a frying pan until it has the color you want. A lighter roux will add a paler color and a milder flavor, a darker roux adds a deeper color and richer flavor.