For years I have been using CF card readers to download my Images from my camera instead of just hooking the camera up to the computer, especially if I have a large amount of cards to download images from. The only problem with the readers is the multiple pins where the CF card mounts into the reader, even with the most careful of use they regally bend or brake. The card reader is then stuffed and no-longer usable Not long ago I came across an SD to CF adapter advertised on Ebay for 12 dollars (Australian currency). SD cards are cheaper and more user friendly. Thank you Ebay for this cool little adapter.
The bending or breaking of CF pins is usually down to using cheap card readers, these can cause the card sockets to become misaligned and then break the pins in either the reader or the camera. I don't think I would use the adaptor in a top of the range camera because you could get some loss of writing speed by using SD cards.
Not everybody can afford a top of the line camera and must use the best they can. CF cards are becoming old technology, so to use a more affordable and a plentiful card format is useful. The loss of some of the writing speed is a minor thing if you don't need a large quantity of rapid fired shots, such as those used in high-end sports photography and the majority on this site don't. I have a canon 1d mark3 and tried the adapter out with rapid multiple shots with the adapter and with just the CF card and noticed no difference I find the adapter I use works fine for everyday use and it should suit most photographers.
I'm not knocking the idea if it works for you then it's great. As for CF cards becoming old technology, that may appear so because of their large size but for write speed there isn't yet an SD card that can touch them. The reason behind it that the CF cards have more pins which allow the data to be transferred in parallel. With the more recent CFast card these are getting even more efficient and development is still going on to get faster data transfer from CF cards, they will be about for a long time yet.
I consider a site such as this is one where you open your mind to different ideas outside of your usual sphere of influence such as cost and past experience. I usually take portrait, landscape and various competition photos which generally don't require a large data download speed, but your comments have peaked my interest so I looked on Youtube about CF cards and data downloads and then Ebay for CF cards with a udma7 seven rating, the result was a sever pain in my wallet, just looking at them but you get what you pay for. Spring weather is just around the corner down here in Tasmania, a time for animal and bird photography. I like to get the best out of my gear So one or two might find there way into my camera bag to try out.