That is a nice offer for some services which are not allowed in any particular country. With that service if a person want to create an account with another country then he will be able to do but the problem here is the risk of hacking as our account is connected with someone else number.
I also do not believe on these type of service for my personal accounts but only for some emergency service I often call off these type of services.
Please tell me that from which country code you provide the phone numbers.