Project looks cool, but forcing people to use MetaMask to buy tokens is not. You'd get more adoption if you open it to other wallet types. What are Ethereum/Mist or Ledger wallet users supposed to do (aside from jumping through hoops)?
MetaMask is a
free browser extension wallet which provides an additional layer of security and is user-friendly for "newbies" who wish to invest.
I can understand that with your experience in crypto and having the hardware wallet Ledger, it might seem like a no brainer to just allow usage of them to buy into the TGE. However, to protect the newer entrants without the right tools, Metamask does give an added advantage over simply creating a MEW wallet.
Hope this clarifies that the team is not making investors jump through hoops, but wish to simplify the process to just a single type of wallet to prevent confusion.