As far as the coil bulbs go, most manufactures have stopped production to find a phospherous that does not produce these rays, others have placed instructions that are more detailed to assist the owners for proper usage, how many actually read it though.
Is one bulb or setup better than others, absolutely. I use a T-Rex MVB which produces plenty of heat and UVB for a bearded dragon, but some I'm sure will chime in and say that the MegaRay is the only way to go, am I saying that it may not be, no, just that there is nothing wrong with it.
The autopsy on the beardie only states that crushed walnut shells were found to block passage. It gives no background as to care. By the looks of things AND the fact that the owner waited a month before bringing it to the vet, tells me neglect of care and probable poor care. It's like saying that I did everything right, I used a MVB bulb, temps were 110 in the basking area and around 80 in the cooler area, I used paper towel as a substrate. What happened, well did you feed it? There are plenty of people that have good intentions in the beginning and get the right products for the setup, but when it comes to care. . .well that is when the problems begin.
For someone who doesn't monitor their BD's health, it doesn't matter what substrate they use, it will not live very long. You can get impaction from the insects you feed, and yes any can cause it, if you don't follow simple guidelines for the age of the dragon you are feeding.
I recently had a little guy pass, I had the temps right, paper towel substrate and was feeding small crickets and phoenixworms, the phoenix worms as the staple, I offered greens everyday and gave a
bath at least everyother day to every day. What went wrong, who knows, I force fed when he stopped eating, his fecal was negative and still he died.
Sometimes though when things happen and the impaction is to blame, you do get the usual "I did everyhting right", when in reality you find out that what they thought was right, was not, like temps and the type of diet.
Do I use crushed walnut, no, why, because there are better options out there.