I "took your advice" and checked. Interesting how you switched from batts to loose fill to make your point. You should run for office.
When insulating a home, it is important to get the overall desired R-value. It's also important that the product provide long-lasting thermal performance. While R-value "per inch" is promoted by some manufacturers, the overall R-value installed is what counts. Fiber glass, or any other insulation can be blown in an attic to nearly any R-value. In order to ensure the expected energy savings, it is important that the insulation does not deteriorate, or settle, over time. Fiber glass batts and rolls do not settle. Fiber glass loose-fill insulations may settle approximately 1 - 3 % resulting in virtually no impact on the thermal performance of the insulation. Cellulose insulation not only settles to a much greater degree (approximately 20%), but also at a significantly higher rate. If cellulose insulation is being considered, make sure the installer understands that most cellulose insulations settle in attic loose fill applications - that's a significant loss of insulating effectiveness. In fact, the Insulation Contractors Association of America recommends that an additional 25% of thickness be added for cellulose insulation to compensate for this extreme loss of R-value.
Fiber glass and cellulose perform very differently in terms of fire safety. Fiber glass insulation is naturally non-combustible because it is made from sand and recycled glass. The insulation requires no additional fire-retardant chemical treatments.
Most facings attached to fiber glass insulation are combustible and should never be left exposed. Other special flame-resistant facings may be left exposed where desired, such as on a basement or crawl space wall.
Cellulose insulation is made primarily of ground-up or shredded newspaper, which is naturally combustible. To protect against fire, cellulose insulation is heavily treated with fire retardant chemicals. Though cellulose is treated with fire retardants, it is not fire proof. We could debate this issue, but its still ground up paper, any way you look at it.
Recycled content? As an industry, fiber glass insulation manufacturers recycle more material by weight (glass cullet - up to 40%) than any other type of insulation used in the building and construction sector.
You can use cellulose, but I wouldn't... that's my opinion.