I was surprised that spoons and cups that have the label "compostable" on them are actually not compostable in most cases. For starters, most compost sites are unable to accept them because they are often confused with regular, non-compostable plastics. Moreover, industrial composting sites, which do have the capacity to compost such plastics, are difficult to come by. As a result, "compostable" bioplastics tend to end up in the same place as regular plastics: the landfill. I had the unfortunate misconception that if a compostable item goes to a landfill, it would compost just as it would in a compost bin, when in reality, those materials are packed so tightly that only anaerobic respiration by bacteria is possible. Unless the landfill has a methane cap to harness the methane produced from this process, this contributes to incredible amounts of greenhouse gas emissions.
BPI certified compostable items are accepted by my city's waste management site, but rather than rely on this, I will continue finding ways to reduce my plastic use, whether that be of traditional plastics or bioplastics.