Whats stopping you 
from using Monero?
I have bought some but it isn’t accepted almost anywhere.
Like many attempts to claim Bitcoin has failed as digital cash, the existence of Lightning has to be ignored to make the argument. I don’t know why one would feel a need to be dishonest about Bitcoin to try and push Monero. Monero should be capable of standing on its own merits, no?
Its mission was to be de- centralized (yes) and private (no).
Monero fulfills both principles.
Can you explain how Lightning isn’t private? This is exactly what I mean. Obviously if you ignore the privacy solutions for Bitcoin there is no privacy with Bitcoin, but that’s not accurately representing reality.
Shielded Zcash is better.
Isn’t it theoretically better if it were always enabled, but suffers from a problem where most Zcash users don’t use it so its actual anonymity set is fairly small? This might be outdated information, I don’t actually follow these things much but thought I’d read that at some point.
Because the differences can be extremely complicated. Cryptocyrrencies are complex, and are not great for throwing out pithy one-liners in a forum context. I suspect there are literally hundreds of white papers from industry veterans and actual mathematics Ph.D.s’ on the subject.
Here is an article that I found, that seems to cover the differences pretty well: Monero vs Lightning Network: Privacy Compared | MoneroSwapper
Lightning is an improvement over standard Bitcoin, but the privacy aspects of a cryptocurrency really need to be baked into the protocol of the underlying cryptographic exchange. You will always make bigger sacrifices by building something private as a side-chain to something not private.
That is a theoretical technical difference, and Monero will match ZCash on that technical level once FCMP++ is implemented. In reality, Monero is much more private than ZCash because it is private by default, which means all Monero users benefit from the privacy. Anyone on this forum can see how important default, not opt-in privacy is, for adoption and privacy.
ZCash is also more centralized than Monero, includes a dev tax, and is accepted in many less places than Monero.
I would be very happy if ZCash became private by default, but it is not.
You admit that Zcash is technically superior. I intentionally mentioned specifically Shielded Zcash so that non-shielded Zcash is less private is not relevant to what I said. Regardless, the fact that you have less privacy than Monero when using non-shielded Zcash has nothing to do with the far superior privacy properties of Shielded Zcash and does not take away from them.
What do you want to buy? There are over 8000 listings on XMRBazaar—a Craigslist built for Monero. Buy some maple syrup? Or perhaps Italian meats?
Perhaps you need an accountant? Monerica - Businesses
Do you need digital goods? https://kycnot.me/, Digital Goods by ProxyStore
But, why though? You can’t just assert something is necessary without reason, especially when it demonstrably is not necessary as the desired result has been achieved without it already.
You quoted what’s called a “conclusion”, and it’s typically placed at the end of a body of writing to briefly summarize and tie together the various points and themes of the work it proceeds.
Which is to say, I think you ignored everything I said prior to the conclusion, because everything I said prior to the conclusion explains why I would come to the conclusion I did. The article I linked goes into greater depth than I am willing to.
You are replying to what’s called a “response”, in which I am addressing the whole of your argument, which as you mentioned is sumnarized by the conclusion. What I am saying in my response, which you might have gleaned if you had actually read it in good faith instead of assuming anyone who disagrees with you must not actually be responding to you (surely how could anyone disagree with you?), is that your conclusion does not actually follow from the points you laid out prior to asserting it. Hence, my response.
If I am missing something where you provide a substantive rationale for your assertion that “the privacy aspects of a cryptocurrency really need to be baked into the protocol of the underlying cryptographic exchange”, please point it out, because I don’t see it. Instead, you seem to have just arrived at it as some kind of divinely inspired axiom of cryptocurrency architecture.
I will reiterate, I don’t see how it is necessary or what end it could be described as necessary for if the same substantive result has already demonstratively been achieved without it.