Yes and yes.
If you pay cash, you'll eliminate all the time and effort involved in obtaining financing.
And cash offers are stronger than offers requiring financing. So, often, people paying cash do offer less. That's a negotiating tactic, and doesn't always work. For instance, if someone owes $300,000 on their mortgage and the house is on the market for $330,000 (essentially enough to pay off the mortgage, pay the real estate agent, and cover other closing costs), and you offer $289,000, all cash, that's probably too low for the seller to be able to accept. But if there's enough equity in the property, you stand a much better chance of having your lower offer accepted.
Hope that helps.