Its a catch 22...
On the heads side of the coin
Other marketplaces do that to try and encourage a buyer to pay closer to what their own automated tool suggested. So, if you reference a well known one that spit out a crazy high value, sure, why not?
Godaddy, Epik, ATOM and Flippa used to have that option I think (haven't checked recently)
On the tails side of the coin
If the well known one spit out a low number or you use an unknown one, it may or may not create doubt.
Note: It's mostly just domain investors that pick apart appraisal tools and avoid them like the plague due to inconsistencies and inaccuracies. Most start ups (For domains in the 3 to 4-figure range), either have no idea about appraisal tools or they just go by the number the marketplace told them the domain listed for sale is worth and that a lower listing price than that evaluation is a discount.
To each their own, but a number on a page with a claim of value will probably be scrutinized by a good acquisitions team (For domains in the 5-figure+ range), whom will research the domain to determine it's actual potential and value before making an offer or engaging the listing.
As someone that analyzes things daily, I like to know how someone got to a number they referenced (Regardless if its in the 3, 4 or 5-figure+ ranges) and do my own due diligence to research it.
It might be more helpful (And digestible for a potential buyer), if there was a breakdown with references as to how the number was formed, rather than just slapping the number up there without any supporting documentation and expecting everyone to just trust it, because you and a tool they never heard of said so.
The breakdown should be part of the fine-print further down as to not overwhelm the buyer with too much reading, but still be there in the event they would like to know how the number was formed, via verifiable references that include supporting data.
That's just my opinion though. Everyone does it differently.
