Catalan-Style Pesto,glorified roux or the best thing since sliced bread?

Picada is a dense, pounded paste of bread, nuts, garlic, olive oil, and other aromatics which originated in the Catalonia region of Spain. It dates back to the thirteenth or fourteenth centuries, as a way to thicken and flavour stews and braises. With its history comes recipes as varied as the cooks themselves. Almonds are traditional, but some picadas call for hazelnuts, pine nuts, or walnuts—sometimes individually, sometimes in combination. Aromatics like saffron, cinnamon, white wine,even dark chocolate, as well as chicken and game livers, are not out of place here.Picada is the Catalan-style pesto you can use on almost everything.It can be used as a condiment to enliven non-Catalan dishes too, sprinkled on top of everything from grilled fish and ribeye steaks, to warm frisee salads and even pasta dishes.Picada is usually stirred into a stew or braise during the final minutes of cooking.
After more than 30 years sniffing out recipes across Spain and publishing them in highly successful cookbooks, journalist and authority on Spanish food Janet Mendel sauces dishes from chicken to codfish balls and Zarzuela with typical picadas,while "Queen of Mediterranean cooking,American food writer Paula Wolfert, claims it has“a deeper and lustier taste than butter or cream,”Well who would have thought?
As Colman Andrews writes in Catalan Cuisine: Vivid Flavors from Spain’s Mediterranean Coast, anyone who has tasted a dish before and after its addition will understand that picada “seems to fill in all the holes, plug in all the gaps in flavour.”

No other European cuisine has anything like picada. 

                                                                              Colman Andrews

Andrews devotes several pages to picada in Catalan Cuisine, referring to it as a “glorified roux,” one that “doesn’t swell up as dramatically or thicken as relentlessly as roux,” and “adds more heart than heft.” He explains that no other European cuisine has anything like picada. Its closest relative is Italy’s pesto, also a pounded mix of garlic, nuts, and herbs, but one that’s unmistakably a sauce; and gremolata, the herb and garlic mixture classically added as a final flourish to osso buco. But no other blends, Andrews writes, come close to picada’s versatility and range.I would have to agree.