If you have read the other manuals written on this subject, you know that the Amazon Echo and Amazon Echo Dot are both devices that stay in one place while you are using them. You can take them to a new place and use them there; however, they need to be connected to Wi-fi in order to access Alexa and other features. You will need to find a nearby plug; the Echo and Echo Dot are not devices that can be used on-the-go.
The Tap is powered by its battery, meaning that if it is charged, you don't need to have it plugged in. Because the Tap does not need to be plugged in and you can connect it to mobile hotspots, you can virtually transport this device to any place you can get cellphone signal. You can turn on your cellphone's mobile hotspot feature and connect your Tap to the hotspot. This means that you can stream music on an excellent speaker when you are outside- at the park, at the beach, at a picnic. Your imagination is your limit.
Additionally, because the Tap is built with Dolby, the music does not get fuzzy when you turn it up. Many speakers can become fuzzy and unclear the louder you turn up the volume. The Tap keeps streaming your music clearly no matter how high you turn it.
If you specifically want to have Alexa in your devices, but you also want to have a great speaker, then you are left with the Amazon Echo and the Tap. The Tap is the cheaper of those options, giving you both a great speaker and the Alexa feature. The Echo Dot gives you the Alexa feature, but it does not have a music built for streaming music.