You're not missing anything. (Well, maybe one downside: see the bottom of this comment.)
MikeC is basically right, but it's likely that the SCTY options will not actually become standard-strike TSLA options; they'll become weird "TSLA1" options (or they might even keep the SCTY symbol, but the deliverable will be Tesla stock). That's what they do with stock-for-stock mergers.
I've been trading puts rather than calls, but yes, there's been a massive premium for SCTY puts over TSLA puts at the "equivalent" stock price (based on the lower end of the range of exchange ratios in Musk's letter). I'd expect a similar situation for calls, which you seem to have found. (I should note that at the .122 exchange ratio, an SCTY $25 is really a TSLA $204.9, not a $200, so take that into account).
At the Chicago Board Options Exchange and the Options Council, they explain what happens with all-stock mergers, and I've linked some of the sources in previous comments. Since you're not paying me, I'm not going to find the links again for you; learn to find 'em yourself. The basic principle is that the options exchange attempts to maintain the same economic meaning of the option after the merger, whatever that is. If 1 share SCTY stock turns into .122 shares TSLA stock, then the deliverable for an SCTY option changes from 100 shares to 12.2 shares. (If 1 share SCTY stock turned into $20 cash, the deliverable would become $2000 cash... see how that works?)
The downside is that after the merger, the SCTY options (or the TSLA1 they turn into) will be extremely thinly traded. If you're planning to hold until expiration or exercise, this is fine. If you were planning to exit the position by buying or selling it, you may not be able to. In fact, SCTY options are *already* extremely thinly traded compared to TSLA options. When I get into SCTY options positions, I do *not* expect to be able to exit those positions by purchase or sale; it may not be possible.
This probably has something to do with the difference between SCTY and TSLA options pricing: a lot of options traders are extreme short-termers who never plan to hold options to expiration or exercise, and the extreme illiquidity of SCTY options would make them avoid those options.