Your definition fails to do that and equals them, while the conventional understanding of speculation refers only to the latter. In other words, selling something with value created (added) is not speculation.
Any (voluntary) sale creates value. It is the goal and motive of the sale.
You seem to be confusing price (exchange value) with economic value. Simply speaking, when you just buy something and then sell it, you don't create new value (benefit) but transfer one.
It seems that YOU are confusing both !
When you buy something, you do that because you think you have more value than what you pay for it.
If you sell something, you do that because you think that you get more money than what you value the thing you are selling.
If I buy an apple, my satisfaction of having an apple is higher than the money I give for it, so there is value creation (there is increase in satisfaction). The one selling the apple appreciates more the money than the apple (maybe to buy an egg which he values more than the money, or the apple). His satisfaction increases too.
This is not different in principle from taking resources like iron ore, oil, labor and so on, and transforming those into a car. Maybe people value that car more than the iron ore, oil, labor and so on. Then value is created. Maybe the car is lousy, and I put in huge amounts of iron ore, oil, labor and so on, and the final value is lower, because the lousy car gives less satisfaction than the loss in iron ore, oil, labor and so on. Then I simply destroyed value.
Production is just a specific case of doing stuff with assets. I can also just transport them in time or in place. I can bring them together and transform them. Each of these actions can create value, or can destroy it.
Value is individual satisfaction.
Price is the exchange rate of goods and services.
Exchange normally implies value creation, and of simply price exchange. Nobody wins "price" in an exchange. But both win normally satisfaction.
Speculation is the idea that I can do something with an asset to win in price exchange, doing something, and another price exchange. The "do" is "transport in time", "transport in space", or even transformation (production). Whether I win or not is dependent on the price of the second exchange, which depends on offer and demand at that moment.
If I buy an apple now to sell it later, I bet on the fact that the price of apples will be higher later than now.
If I buy an apple here, to sell it there, I bet on the fact that the price of apples there will be higher than here.
If I buy iron ore, oil and labor and want to sell a car that I made out of it, I bet on the fact that iron ore, oil and labor are cheaper than the car.