They arent for every sacrifice deck, but the burst of card draw makes them quite useful, especially if you can recur the sacrificed creature for further value
There are two very simple reasons why this land is so valuable: it was only printed in one set, Arabian Nights, making it a part of the Reserved List, a collection of cards from Magics early days that the company has promised never to reprint
To gain Josef's trust, the party goes and frees the enslaved townspeople and acquires some mythril for later
Pinging any target every time a human enters the battlefield can allow you to build a massive advantage by either damaging your opponents or picking off their creatures
The addition of Cori-Steel Cutter gave the deck a big boost, allowing you to put on a lot of pressure and grind through removal
Aside from shocklands, Return to Ravnica gives us some completely new cards that look to be playable in Modern