Frequently users ask the same question. Why samples from Levant, Iran, Anatolia and Caucasus are used to model ancient and modern samples from Armenia, if ancient samples from Armenia are alrwady available.
For the academic papers the answer to this question is simple. They want to have an universal model which they can use for any sample from any time in Near East. For this reason they use the extreme, (from genetic point of view), homogenous populations available from Near East. Which by the way are not necessarily the most successful populations inside Near East.
Anatolian Neolithic farmers for example had a successful expansion in Europe. But in their homeland their ancestry dropped in Chalcolithic when new migrants from historic Armenia/North Mesopotamia settled there. The same is true for Caucasian hunters, Levant Neolithic and Zagros/Iran Neolithic.
All those populations had a serious dilution of their ancestry in Chalcolithic. But given that the main "coupables" of this dilution themselves can be modeled as a mixture of this 4 populations then scholars prefer to use only those 4 source, to avoid too much complication.
If in Anatolian context they say there is an increase of Caucasus then this mean usually a migration from historic Armenia. But an increase of Caucasus in Steppe do not automatically mean a migration from Armenia. If they say an increase in Iran Neo in Anatolia then it means a migration from North Mesopotamia. But an increase of Iran_Neo in Central Asia do not mean migration from Mesopotamia. Etc etc. You must always keep in mind the geography to understand this strange language. It's not a conspiracy but rather an easy way for them.
There are also technical reasons. Old samples from Mesopotamia and historic Armenia are rare and they are not as homogenous as one would want them to be. Most probably in the future this situation will change.
As for citizens, they can do whatever they want. There is no any rule that forbids the use of ancient Neolithic samples from Armenia. I always do that in my charts and they give better fits than just 4 pops from Near East. We can go further and experiment with more samples from ancient Armenia. We have some examples for that also in this group. But they are some constraints. Using too much samples with similar ancestries can create results that are hard to understand and very volatile. For example You will have apparent sharp differences between quite close pops