Question about selling covered calls, with hypothetical scenario

I am curious about selling covered calls, but I feel like I'm missing some hidden element of risk.

Let's say a stock is $10.00, and you buy 100 shares. You now sell 1 contract (100 shares) at a strike price of $12.00 for $0.50 each ($50 contract).

Am I understanding how selling covered calls work, in that the following are the possible outcomes?

1. Share price rises to strike price ($12) – You make $200.00 from the stock increasing, plus $50 for the sale of the contract. You are obligated to sell 100 shares for $12.00 each to the buyer. Your net profit is $5.00.
2. Price goes way up, (example, share price increase to $50.00) – You make $200.00 from the stock increasing, but you don't profit any further than your strike price. Also, $5 for the sale of the contract. You are obligated to sell your 100 shares for $12.00 each to the buyer. Your net profit is $250.00.
3. Price goes down (example, share price decrease to $8.00) – You lose $200 from the stock decreasing. You gain $50.00 from the sale of the contract. Net loss – $150

Is there any other possible thing that can happen, or am I missing some hidden risk? If I'm not missing something, then if anyone has significant shares of any given company, for what reason would they NOT be selling covered calls all day every day, at strike prices that are unlikely to occur?

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