NEW YORK ( MainStreet) — Would you trust a wireless carrier to be your bank?

T-Mobile and Sprint have made that question one we have to ask ourselves.

The other question you have to ask yourself: is this all the bank you need?

The answer just may be yes.

The biggest splash has been made by self-proclaimed UnCarrier T-Mobile's recent - and loud -- debut of its Mobile Money offering which basically lets customers do their banking via mobile app and also in the company's 3,000 storefronts. The account's operative word is free.

Customers get fee-free withdrawals from 42,000 Allpoint ATM locations, $0 reload fees at T-Mobile stores, $0 monthly maintenance fees and $0 purchase fees. There's no minimum balance requirement.

A prepaid Visa card is built into Mobile Money and that means merchant acceptance is high.

What you cannot do is write paper checks - but you can pay bills electronically.

However, you can deposit paper checks, using the mobile remote deposit capture function in the T-Mobile app.

What prompted T-Mobile to plunge into banking?

"Millions of Americans pay outrageous fees to check cashers, payday lenders and other predatory businesses – just for the right to use their own money. Mobile Money shifts the balance of power for T-Mobile customers and keeps more money in their pockets," John Legere, chief executive officer of T-Mobile, said in a press statement.

Even better, T-Mobile is on record saying it sees no necessity to turn a profit from its banking operation.

Sprint, which has now rolled out its mobile wallet to customers of its Boost prepaid cellular service as well as some users of the Sprint post-paid cellular plans, also has said it has no compulsion to make money directly from banking.

Kevin McGinnis, vice president of development and technology at Pinsight Media+, a mobile media company associated with Sprint, said in an interview: "It's early to say if we will accrue financial benefits. It may improve retention in a no contract world."

McGinnis added: "We want to improve the experiences for our customers. This will generate greater loyalties. It will unlock future revenue streams. It doesn't have to be a profit stream."

The Sprint product too offers much the same services as T-Mobile's mobile wallet, and both have much in common with the American Express - Walmart Bluebird non-bank.

Fact: digital technologies, especially of the mobile variety, have made it inexpensive to set up and operate what looks like a bank. And if offering banking services to cellular customers reduces churn - the plague on profits at every carrier - it's a home-run for the carrier.

At least some experts think T-Mobile and Sprint are onto something.

"The concept that you can only get a bank account at a 'bank' has long been dispelled, but perhaps the greatest opportunity for the likes of T-Mobile is to lead the charge in the mobile, downloadable bank account," said Brett King, founder of Movenbank, a mobile only bank.