Who is collecting these bags that they put through your letter box? It is a registered charity? Or just a company?
As the particular request for handbags rang a bit of an alarm here. There are places (companies) that get in donations and they resell these items in bales to poorer countries. Ie one that I live in. There are bales of everything you can imagine available...but for a price. They aren't being donated, only sold.
What happens , person here will buy a handbag bale, trainer bale, dresses bale etc and then it's opened up and literally piled up high, sometime on the corner of a street, but also sometimes into smaller shops. There is also a term for these 'shops', translated into English the place is called 'the bend down store' (as people are sifting through stuff which is in the ground ). People came along and sift through the piles and buy single items for really cheap prices. But no charity (afaik) has benefited here.
People are donating in good faith that it is always going to a good cause. It's not always the case. People here are making a lot of money bringing in and selling bales.
Go have a search on Tiktok, it's quite an eye opener.
So as I see the other side, if you want to donate to a cause, take it to that particular registered place. It's very possible that charity shops excess stock are also sold on like this, as I have seen items come in via these bales with heart foundation and a fair few other charity labels still on. In my mind, then at least the charity would benefit somewhat then, even if they only got rag value.