What are the disadvantages of VeChain?

Could you please elaborate on the drawbacks of VeChain? I'm particularly interested in understanding its scalability challenges, if any, as well as any concerns surrounding its dependency on centralized entities for certain functions. Additionally, I'd like to know if there are any security vulnerabilities that have been identified in its blockchain technology. Lastly, could you discuss any potential regulatory challenges that VeChain might face in the future? Thank you for your insights.