Makes shopping or filling out forms online much easier. It is a much more secure way to exchange money throught the internet instead of just typing your debit card in blindly. Digital Wallets also help you create stronger passwords without you having to worry about if you will remember it. Source
It can do other things in addition to transfering money such as store your DOB and verify your age for age-restricted items such as tobacco or alcohol. It combats shoppers from abandoning their shopping online due to frustration (which 25% of e-shoppers do), by storing pre-fillable information such as your name, address, email address, CC# etc. Source
Because they are connected to the internet they are suseptable to being hacked, even though they are encrypted. Loss of privacy due to your infomation being store together and more trackable by marketing companies. Source
American Express, Apple Pay, Google Pay, Bank of America, Paypal, Amazon Source
Yes, I use Google pay to transfer money between people I know (like my husband for groceries etc.), and collect payment for freelance work. I also use Paypal to check out more securely through websites and pay certain bills which do not allow auto-debit via my routing number for my checking account. (I REALLY hate it if anything is connected to my debit card, and then when it expires I have 30 different auto-payments to fix). Source