Freeview offers these channels:
https://www.freeview.co.uk/app/uploads/2016/10/Freeview-Channel-Guide-2016.pdf
A generic satellite receiver gets you these channels:
https://en.wikipedia.org/wiki/List_of_free-to-air_channels_at_28%C2%B0E
A Sky box without a subscription acts as a generic satellite receiver.
A Freesat receiver is configured to natively receive just a
subset of those FTA channels
http://www.freesat.co.uk/channels
but can be manually configured to receive the missing ones.
Up until fairly recently a major disadvantage (for many people) of Freesat was that UKTV's subscription-free services, which are available on Freeview, weren't available via satellite. Most of them have now been added to the line-up (meaning that Drama, Yesterday and Really are now available to Freesat viewers) but Dave still can't be received via satellite.
So satellite reception offers more channels (but many people don't want things like obscure religious or Asian channels anyway) albeit with the loss of Dave (and possibly one or two other little-watched channels).