In reply to a post by MrSaffron:

Perhaps you need to look at why lamp posts are a common wi-fi hotspot location in cities...

i.e. have power and some height and are existing furniture with small space inside.

The height means line of sight to a lot of people nearby when using the 8 GHz to 28 GHz bands and this also means while more masts that lower power levels than a bigger 4G mast on top of a block of flats or office building.