It doesn't completely remove the need for a healer in the party on its own. It makes healers less useful. And another thing that makes them less useful is free "help" action that brings a person back up with 1 hp. However they are still useful because of Healing Word, which is a bonus action. This is I think the only reason to have a healing character in the party: to be able to healing word someone (heal them at range as bonus action) and attack on the same turn. This only makes sense if the other character is down though. Food is useful to allow for more hp gain as there is only one short rest per day available.