Generating true entropy is really, really painful. Rolling dice 100 times, or flipping coins 256 times is not easy. It also doesn't help that most people have the attention span of insects.

I've argued in the past that the easiest entropy is very thoroughly shuffling a deck of cards and using the first 40 or so cards. I actually coded this feature into Armory back in the day. The problem with that one is it's not so easy to convert those cards to a seed phrase, at least without some hardware device. Still, it's better than the hardware generating the seed phrase on your behalf.