Do saffron threads add flavor, or just color?

Saffron does add a slight creamy/ smoky aroma to dishes that turmeric does not. Saffron gives a soft mild buttery yellow color whereas turmerics shade is much more intense.

Without seeing the recipe, let me put it this way: Saffron isn't the most expensive spice in the world because of its color.

The flavor is very slight, the color similar to turmeric without the harshness.
I would not do a paella without it.

Nice one, ChefOno. Made me chuckle.

The flavour can actually be very overpowering and distinct if used excessively, so be careful with those pinches. When using, brew it like a tea in a few Tbsps of hot water before adding it to your dish - this draws out the flavour (and allows you to use fewer strands).

Good one ChefOno. Saffron does add flavor and there are times when I go overboard with it. What does not add flavor is saffron powder which is made from safflower and all that does is add color. And then there are dishes where turmeric just does not belong...period.

Thanks for the passive-aggressive help ChefOno. : ) I now know... what it isn't.
Thanks everyone~ I'm sure you've just improved my Moroccan Lentils immeasurably.

if you use high quality saffron, try to use it not so much, just couple of stigmas will give food the real gold coloring and the taste is slightly bitter if you taste it directly, that is why I prefer use saffron properly. You can also use saffron powder, that you can use for dressing also .
http://www.exirsaffron.com/pure-saffron-powder

Turmeric will never add the specific unique flavours of saffron. Saffron works in various ways depending on saffron quality (very difficult to find real and good saffron, fraud is massive), ingredients in your recipe, cooking procedure, dosage, etc. It makes this spice somehow alchemical and a bit difficult to use : it may fade away as well as overpower and ruin the gustative landscape. If you are just after adding color to your dish, use anything cheaper than saffron. But if you have good quality saffron at hand, use it since it deteriorates with time and loses its powers after 4 years postharvest. This website teaches a lot on saffron : saffron-crocuses.com