My favourite use for tires is as artificial reefs for encouraging biodiversity in coastal areas, and as coastal defenses. Underwater, tires are very stable, leach minimally small amounts of toxins, compared to the amounts that are eroded on the roads and washed off into surface water waste. They are resistant to erosion by wave action and shingle, have a large surface area to volume ratio and offer a range of habitats to both sessile and vagile sea life. This can open up areas of enterprise based on fishing, which otherwise would not exist, in areas with flat underlying bedrock that provided only limited habitats.
In coastal areas prone to erosion, reefs can absorb most of the wave energy which would otherwise exacerbate coastal erosion, and provide tidal lagoons safe for bathing, and other leisure activities and free of dangerous currents and rip-tides. Because they are primarily rubber, the construction could be made collision-safe for marine vessels. Indeed, they could also be used for land reclaimation.
As well as not presenting a visible eyesore, there is also no potential for a long term fire hazard, as occurs in landfill dumps. If there is an unforseen environmental side effect in any area where used, such as undesirable silting, tires may be readily reclaimed, or the structure modified to minimize the problem.
There are many ways to stabilize the reef, e.g steel piles driven into the substratum or cutting tyres so that they can be made to catenate, or chain together, or linking with nylon ties, ropes or chains, or ballasting with shingle, silt or concrete.