You may still need a cordless phone in the age of smartphones and internet. You will need one when tehre is no power. Your kids (who have no smartphones) will need to use the cordless phone to make emergency calls. Moreover, cellular reception may not be that great, or even temperoraily down in yoru area.

Most quality cordless phones now come with DECT 6.0 standard. This helps ensure that calls on a cordless phone come through clearly and don’t interfere with any other radio devices in your home. 

Quality cordless phones have full-duplex speakerphone, thus both sides can continue to speak at the same time, unlike teh walkie talkies where only one can speak at a time (this is called half-duplex speaker).

The best cordless phone for most people: AT&T TL96273 (quality audio even at longer distances, great enough pricing)

The best basic cordless phone: VTech CS6719 (good range and voice clarity, no bluetootth, but great prices)