hugopal if it’s good then why waste it in a smashed form?
Minced beef should be cooked through, as it’s otherwise a breeding ground for bacteria. Steak can be eaten rare (or medium of whatever) because the interior of the steak has always been protected. Minced beef, not so much.
Smash burgers are popular because they allow for the beef to be cooked through safely, while maximising the maillard reaction - the caramelisation that occurs when the meat is cooked to a high enough heat. If decent quality beef is being used in them, I think they taste better than the equivalent weight in a single patty, but that’s my tastes…
Far more important (IMO etc etc) is using a top quality mince, made with enough fat. There’s an amazing butcher about 400m up the road from me in Brighton. When I started shopping there, I asked the owner what was in his mince mix. He uses a combination of chuck, brisket and short-rib, and about 80% to 20% fat. His burgers are fucking fantastic - so much so, that I’ve stopped making my own at home. 2 × 4oz balls of mince, smashed on the flat plate on my BBQ makes a sensational burger.