Income tax is a temporary (technically) tax which penalises hard work and savings (double taxation). Replacing it with VAT would make citizens' lives easier and also penalise consumption which would be a 'green' approach to take. Would enable VAT to include a resources element to make use of resources more expensive and keep items such as food etc cheaper.
Why is this idea important?
Simplification of tax is vital to any free society. People must know what they are going to pay and why and must not be penalised for working. Rather they should incur taxes for consuming.
It is consumption which damages the environment, which requires regulations (though many less than we have) to monitor, police to prevent theft etc etc.