what is the best and safe bank or wallet to store USD ?
Software wallet is well safe compare to other wallet which scammer can have access to their money.
What software wallet are you determining? The software wallet you determined is the crypto wallet that we frequently use in our mobile phones and computers that you need to use an internet connection to store cryptocurrencies. I believe that every online or mobile wallet is hackable because hackers can easily access your wallets if used online. So the safest way to keep a significant amount of money or cryptocurrencies in hardware wallets because experts guarantee them that it is safe and secured, even you frequently make transactions online.