The best reason not to use it on beds is it doesn't provide any nutrients to the soil.

I'd feel comfortable using it on non-growing areas, like pathways and such, but I prefer my mulch to break down and add good organic matter to the soil.

Any wood mulch product will eventually break down and can supply nutrients back to the soil - it just takes longer than most other types of organic mulches. Playground mulch is not all that different from using bark or wood chips as a mulch, although I would refrain from using it to mulch edible crops (glues and other additives may leach some potential toxins) and for shallow rooted plants like annual or perennials where there may be some nitrogen depletion at the soil surface, but it is fine to use around woody plants like trees and shrubs.

My mistake. The first thing that leapt into my mind when I read "engineered wood mulch" was the crumb rubber being sold for playground cover.

For the Camano garden we buy cedar play chips specifically for mulching all plants, including herbaceous ones. Like them much better than bark or other smelly, crust-forming moldy mulches.

For the other place we use free wood chips from an arborist. Not as clean and uniform as the purchased cedar play chips and very moldy (at first) but works great otherwise - except the time giant morning glory (Calystegia sepium) came with some.

Here is a link that might be useful: Bark Mulch