And they were big on bitcoin investing.

Bitcoin 

Try asking your banker to loan you money for 30 years to buy yourself some stock or bitcoin lol.

They're not free, but they're reasonably priced.Renters with bank accounts simply pair their bank account to the service and set an authorization date between the 1st and the 5th of the month.Renters without bank accounts can pay with Bitcoin, and you receive their payment in dollars unless you elect otherwise.

Some IT people build extra computers to mine bitcoin and other cryptocurrencies, or set up small labs (consisting of a few computers, servers, and some networking equipment that would normally be found in a business) to practice for IT certification exams.I agree that shared utilities with one tenant paying is a recipe for disaster.

It's kind of like my friend in Brazil this year who asked me if she could make money with Cryptocurrency or Bitcoin?

You get one guy mining Bitcoin and it will eat you alive.

Bit coins are  always a mess to normal people. last day in the cafe somebody told me that Bitcoins are safer than conventional currency notes and soon or later they will replace other currency standards.

For example, bitcoin becomes popular and now he’s all over it; now inflation becomes popular and everyone and him that’s all they talk about.

I truly appreciate your honest comment, which (unfortunately) confirms my concern, and provides further insight.The following site also has a nice overview of how safe, from a seller's perspective, are various payment methods: https://en.bitcoin.it/wiki/Payment_methods (Note: I have not the faintest clue what a bitcoin is, but they seem to have the same problem that we have: safe electronic payment methods.)In summary, I conclude that there is no suitable electronic payment method for rent collection, that is governed by the rule of law rather than the judgement of private intermediaries the rules of which can be gamed, and that cannot be reversed at will by a smart "professional" renter.