Goths get that space for free.
If you have that extra resource (some 800 each of wood and gold) to research it, probably you are already winning the game.
If you are going above 100 vils that again translates that you are dominating the game already. Unless you are in a team game with terrible allies.
So that UT is pretty useless endgame tech as an investment.
I hate when one civ’s civ bonus is another civ’s expensive unique tech. Crappiest civ designing. Unique Techs should always be more effective than civ bonuses or atleast be unique enough to justify.