I dislike the way they're sold, though. No problem if they offer a product that some people might want, but I think they invent unrealistic scenarios and give out a message that you're 'doing the right thing' rather than doing what you have actively chosen for yourself.
It's also a bit odd, imho, as your funeral isn't actually for you: you're deciding whether/how your loved ones want to memorialise you, which may not be what they wanted at all, if you don't discuss things.
I've also noticed that at least one of them has started acknowledging that some people will want a service/gathering, and is suggesting that you save money by having a direct cremation instead of a funeral, but then spend the money you saved on something that many people would consider to be something suspiciously funeral-like!