Cash is so 1990's. Credit cards are so 2000. Mobile payments are truly the future but adoption is slow by consumers and by retailers.
I love the convenience of securing and paying for Uber on my phone. It's not a true mobile payment, but the experience of not pulling out my money clip is so nice. So I just activated Android Pay and Samsung Pay (I'm not sure which I'll use more). I have used Square on my mobile phone before where merchants accept square. It's awesome.
When I go grocery shopping, I will likely be able to grab my phone and be done. I may not need my wallet eventually for many trips.
Samsung Pay has the advantage that it can simulate the credit card even if the NFC is not available. Android Pay only works if the credit card machine works with NFC. Apple Pay for Apple users only works if the machines support Apple.
Hotels are starting to use phones as keys to enter your room. More and more, your phone is your world. Whatever phone you are one, setup the payments feature (apple, android, samsung) and start to experience it. It's a great way to get comfortable with what is coming. I expect that in 3 years, it will be very common for us to pay with our phones in the US like it is in many other places in the world.
As far as security, it's far more secure than a card. Properly secure your device and you'll be fine.