1. They always have low users which means they have nothing new to offer,even if new users try them out,once they don't see any thing new they bounce back to their old wallet, repetitive at work
2. Many new wallets on playstore can't be trusted,they have different set of aims, some have access to your private keys but they will fool users thinking you are the only one in control of the private keys and some don't give out private keys to users,they work as online wallet
Wallet for me is an asset. A very important asset value. If the wallet required to receive the results of the bounties is MEW or MetaMask, then that's all I believe.