You don't know what happens after your donations have gone to a charity shop either other than that they will either be put in the bin as unsaleable or sold for an often bargain price. There are many people out there looking for charity shop bargains they can sell on at a profit.
I tend to put larger, unwieldy or even broken items on Freecycle.
I managed to move on lots of garden stuff. Hundreds of plastic pots, big heavy terracotta pots, a cold frame, tools, paviors from an abandoned project, also those miscellaneous items that accumulate in the shed. They went to a young couple who were starting an allotment. Several months later they called around to say thank you again and give me a box of veg they had grown!
An old portable hi-fi system went to a man who organised entertainment in a local care home.
Curtains and rugs went to an elderly man who was having to start again after a major life change.
Old bikes went to a man who was going to either renovate them or use the spares.
Half empty tins of different shades of neutral paint went to a woman who was organising local scouts to paint their hut. She said she was going to tip it all into big buckets, stir it up and see what colour she got!
Everyone has a story.
There's more effort involved in freecycling. You've got to list and keep a watch on the items and organise collection. All I can say is try a few items and see how you get on.