Intrinsic value is the the difference between the in the money strike price and the underlying price. For example, a $10 Strike Call would have an intrinsic value of $1 if the underlying price was $11, a $12 call would have zero intrinsic value. Both options likely have a market price of more than there intrinsic value. I.e the $10 Strike will cost $1.50 and the the $12 strike will have a market price of $0.35. The value above the intrinsic value is based on the time remaining to option expiration and the implied volatility of the market.
The bid-ask spread is an artifact of there being a market, just like there is in the underlying market. You can make money off of thee bid ask spread if you are market making or scalping, you can make money off the difference in strike prices (intrinsic value) if you are making directional plays, and you can make money off of changes in volatitliy of you are making a volatility/time play.... So the answer to your question is both or neither.
Options are much different than the underlying. There is an additional component: time
I recommend you get the Nattenberg book: Options Volatility and Pricing before you even consider putting an a real money options trade. If you don't understand the content of the book... stay away from options