I tried this card in my pure seeker Ursula Downs deck that focused on mobility. I was playing on STANDARD difficulty. In my experience this card is mediocre or even bad if you plan to use it just to enhance your economy. The problem is that in order for this card to be worth, you have to use it to play a card that costs 4 resources or more, because if not you are just saving 2 resources or even less , which is quite bad considering that Emergency Cache gives you 3 resources without the risk of having to pass a test to get them.
The fact that the only seeker asset that costs 4 is Dr. Milan makes things even worst because you want to have him in play before using Unearth the Ancients, not only because of his reaction ability but specially for his +1 intellect. What I mean is that without Milan's +1 Intellect you are probably just sitting at 5 or 6 intellect at best and this makes passing the 4 investigation test quite a gamble without committing any more resources or cards (which would make playing Unearth the ancients meaningless). This situation gets even worst on Hard or Expert difficulty and if you consider the negative affects of failing a test if you draw the wrong chaos token. This card is therefore almost useless to summon the only asset it would be worth using it for, namely Dr. Milan.
The bonus card if you use it to play a relic is also mediocre, considering that there are not much seeker relics as of now (3 I think) and they cost 3 or less resources.
Some smart player would say: Hey but you can use this card in combination with Ursula Downs ability and the asset Fieldwork to make it worth but the answer will still be this card is bad, because if you play Unearth the Ancients with Ursula's ability you are not getting a free action or making it fast, remember you could have most likely used Ursula's ability to investigate normally, get clues and get closer to victory. Fieldwork is good to have indeed if you are using this card, but having to pull a combo to effectively use a card with a mediocre effect is obviously not worth your time and effort.
You can of course also use this card in combination with Rex Murphy's ability and a cheap asset like Magnifying Glass and even maybe a Double or Nothing to get some free clues in a high shroud location. I personally haven't tried this cheese strategy yet but I think that it isn't great either (and I am not even sure if the rules allow it). It lacks consistency because you need to much conditions to pull it off and there are allot easier ways to investigate in high shrouded locations for seekers.
In conclusion I think it is a pity that such a thematic card has no place in the current meta. I hope that in the future an XP upgrade will make it worth considering.