she was thought to be too easy to read, and to have attitudes that were borderline racist; libraries often didn't stock her works (claiming, reasonably enough, that they were cheap and easy to buy and that they had better work to spend their money on). When the books are reprinted nowadays, they tend to have the sneering at goblins and gollies removed.
She was not a very nice person at all in real life, it seems; but it seems one of her daughters is very scathing of her and the other defends her; so all the stories may not be perfectly true.