Pen-and-paper role-playing games (RPGs) began as an expansion of rules for historical tabletop miniatures wargames. Tabletop wargame rules were concerned with creating accurate simulations of historical battles -- including medieval battles, such as Agincourt. Early RPGs modeled "heroes" as having the equivalent strength of several ordinary soldiers, and added rules for fantastic creatures, magic, and advanced technology. But the rules kept realism as the base case, so an ordinary soldier could fight, travel, heal, etc. in a manner approximating real life unless assisted by magic or advanced technology.
Imposing realistic times for travel and healing worked in the pen-and-paper game since all the players typically formed a single "party", and the referee could arbitrarily move the time-line ahead to skip weeks of boring travel or healing. This flexibility matched that which naturally happened in the opposite direction, where a few minutes of simulated combat time often took hours of real time to resolve. This freedom to manipulate the time-line was retained when RPGs were first moved onto computers. Many single player computer RPGs are still turn-based, and allow the player (sometimes controlling an entire party) to stop time while providing orders to each character. Again a few minutes of simulated combat can take longer to resolve (though computerization makes fast resolution much easier). And many games still allow time to be sped up during travel or healing.
Unfortunately this flexibility disappears with massively-multiplayer online RPGs. These provide the same persistent world model for all the players, so the time-line must move forward at the same fixed rate for everyone. A "realistic" mechanic for healing or travel would impose an unacceptable level of boredom on the players. Instead these games allow characters (even without specialized magical or technological assistance) to quickly heal and travel long distances between encounters.
This common mechanic from online RPGs is currently filtering back into the newest revisions of classic paper-and-pencil RPGs. The "old school gamers" are understandably concerned and confused. They don't see the need, since the referee is always free to speed up the time-line. And those from a simulation (especially miniatures) background don't like the loss of realism.