Between the Daytona and Speedmaster(not even sure which one you mean which is part of the problem, see above) I really don't see any comparison. They are just different watches in quality, workmanship and just the way they feel. Kind of like asking why most people on SF would prefer an Isaia or Kiton blue suit over a Suit Supply blue suit. Nothing wrong with Suit Supply but just not the same.
I would point out that Omega is not, and doesn't try to play, in the same league as Rolex. In fact the NYT had an interview with Omega's CEO yesterday who stated the average price for its watches is 7k and they have moved up a lot but plan to stay there. Nothing wrong with Omega but that is just the way it is.
It all comes down to what you like and are happy with. You prefer a Speedmaster? Then get one and wear it and enjoy it in good health.
Daytonas have been around for more than 50 years. It has been worn in various forms by some of the very successful race car drivers in history (Hurley Haywood, Sir Jackie Stewart, Paul Newman). You talk about "Pedigree" and the Daytona's pedigree, is that of a watch that has evolved constantly with improvements being to its movement during the course of production. Rolex cal 4130 considered one of the best designed chronograph movement regardless of price. A lot has been written about each generation of Daytonas, in various watch books, articles, and online (so if you want to learn more about their heritage/history...just do some research).
When one considers the Speedy the only model I'd consider is the Speedy Pro (none of the others interest me). It has nice history being the moon watch, but they stopped using the movement that went to the moon, cal 321, many years ago. Modern versions cut some corners using a few plastic parts. So it isn't quite the same watch and I'm not sure I'd consider plastic parts an improvement. Also, I've said it before so I will keep it short, Omega does far too many Anniversary editions (such that they don't seem that special or limited), and they have even made Speedys that look like vintage Exotic Dial/PN Rolex Daytonas. I just don't understand making an Speedy that looks like a Daytona?
As for the price, the Speedy has always been a very good value. Its one of its main advantages. However, if one paid what the Daytona listed for, the resale value of steel ones far exceeded the savings one had by purchasing a Speedy Pro. I could easily sell my steel 16520 for 2 to 3 times what I paid for it when new, and my 116520 was purchased several years ago, and regardless of what the market does (now with ceramic ones available) I could still sell it for 40-50% more than I paid for it. So each watch has a price advantage in a sense.
For me the the pros of the Daytona - they are automatics so I don't have to wind it each day if I'm in a hurry.
-they are more water resistant than Speedy Pros, which is advantageous if vacationing to beach area or using pools.
-traditionally much higher demand and higher resale value.
-in my friend's experience Rolex has a bit better quality control (than Omega in general, one of my collector friends went through 3 defective Omegas, granted all were Seamasters) before going with a Speedy Pro and not having any issues.
- I prefer the dial layout, screw down pushers, case and oyster bracelet. I do wish they would go back to using a brushed finish on the lugs but I can live with them as they are.
In my collection, I try to purchase pieces that I feel I could live with if I could only have one watch. I used a Daytona as a daily wearer for 5 years. It could be a do everything watch for me, if I could only have 1 watch. While I like the Speedy Pro...there have always been others