There is one thing that anyone considering a purchase of one of these devices should bear in mind ..... some dongles' power requirements exceed the spec for what is available on a standard USB port.
In that case either the device should be capable of supplying the extra power - mentioned in its spec - or else have two USB ports so that an adapter can be used to draw power from both for the dongle.
Me thinks You are missing the point

. The point is that the ordinary routers that You (probably) have are AC/DC powered and "stationary" this router is USB powered and it's mobile. For example if You meet with business partners and You want a quick (meaning without fuss) internet connection - boom there it is... Or am I missing the point? LOL
No didn't miss it

Of course none of those I mention were designed to be portable ....

...... but the portability was not the main thrust of the thread, as I read it

I have been thinking a little about the use of a battery ...... and have not found a use for it ..... I certainly never met with any business contacts (for business purposes

) where there was no mains power outlet.
I wonder how long a battery would last ..... the dongle can take 500mA or more .... and then it would need recharging once the battery died. It *may* also become rather intermittent as the battery is discharging.
Battery power seems a nice idea ...... but I wonder how useful it would really be in real-life situations.
Would be interesting to hear comments from someone who uses one .....