My take is that to cook beef/steaks medium to well done they have to be well marbled. Fillet does not have enough fat at all to be cooked other than rare/medium.
The fattier cuts of steak and also beef can be cooked so that there is no blood left ( always puts off the non-carnivor <!-- s:? --><img src="{SMILIES_PATH}/icon_confused.gif" alt="

" title="Confused" /><!-- s:? --> ) but then the fat melts into the meat and gives a moistness to the meat.
Remember in the good old days of frequent flying with Aer Lingus and other posh airlines? On registering there were all sorts of boxes to tick:
Vegetarian <!-- s:cry: --><img src="{SMILIES_PATH}/icon_cry.gif" alt="

" title="Crying or Very sad" /><!-- s:cry: -->
Kosher <!-- s:? --><img src="{SMILIES_PATH}/icon_confused.gif" alt="

" title="Confused" /><!-- s:? -->
Halal <!-- s:? --><img src="{SMILIES_PATH}/icon_confused.gif" alt="

" title="Confused" /><!-- s:? -->
Other <!-- s:? --><img src="{SMILIES_PATH}/icon_confused.gif" alt="

" title="Confused" /><!-- s:? -->
There was never a box for "CARNIVOR"
NJoy
Will