This might not be entirely true. What do you think about hardware wallets than. There are hardware cold storage wallets like ledger nano s that support lots of altcoins, and I think that hardware wallets are safer than any other software or jot wallet. Even if the deva created a proprietary wallet, if an hardware wallet can support that specific coin, I will choose the cold wallet. It is much safer. And cooler, if you ask me. It is nice to have a piece of hardware specifically taking care of your beloved coins