I don’t own ZM, but why is optionality considered a desirable thing? …Over and over we’ve seen companies try to stretch itself too thin and offer too many products and have it hurt shareholder returns because there’s not enough focus.
You mean like Amazon (“on-line book seller”), Apple (“Mac Desktop Computer maker”) and Google (“Search”), Square (“Payments company”), MELI (On-line marketplace), etc, ect. etc…? 
The simple answer is that companies that are rigidly focused on delivering on one product are more fragile and susceptible to being disrupted.
Here is a lesson in ‘why optionality matters’ from the great investor, David Gardner:
https://www.fool.com/investing/2017/10/30/9-self-evident-foo…
David Gardner: No. 2: I’ll just call it by the watchword we often use which is “optionality.” Principle No. 2 is basically that the best businesses are able to evolve. Why does that matter? Well, just like in biological evolution, changes in external circumstances happen and your organization needs to both be aware of those things and be adjusting itself to be relevant, and or successful, and or just survive into the next era by evolving. And one of the best ways that innovative companies manage to do this is often they have a second or third trick, and we call that, again, optionality. It means you have multiple possible futures.
The strongest business of our time, I think, is probably Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL). Looking across all of Alphabet’s different businesses starting with Google – and then looking across the globe and seeing all the different places that it is doing its Googly things – that is incredibly strong and the optionality, there, is enviable. I hold that up even over something like Amazon or Apple, because I just believe that Alphabet is operating across more fronts and doing more interesting stuff than any other company in the world.
Now, very few organizations are going to be like that, and very few stocks that you and I will pick have that kind of resilience. As long as you understand the concept that just like in biological evolution it’s going to be really important when external circumstances change – the Ice Age hits – it’s going to be really important for companies to recognize that it’s getting cold, let’s say, and they need to stop doing this and start doing this other thing.
And the ones that can actually do that – that have the leadership, that have the vision, that have the strength to actually be able to implement those changes [and permission from the markets, and customers, and partners to evolve] – those are the companies that you and I want to own.
As an aside, here is David Gardner’s current stock picking record over two decades for the Stock Advisor service:
David +570.6%
S&P 500 +87.0%
Not bad!
Fool on! Swift…