Indeed, investment in the ETH don't differ from investment in the METH.
Why then should I buy METH if I can buy ETH?
There is a point when all the METH tokens are redeemed. It's like a hardcap that the usual ICO used to use. But unlike the usual ICO you can refund your ETH at any wished time, just sending METH tokens you own back to the METH smart contract.
At second stage all the tokens are in the hands of investors. From this time due to the METH tokens deficit, there is a high probability of growth.