On Vast an RTX 3090 costs about $ 0.10 / hour. Forty of these would be $ 4.00 / hour and thus $ 96 per day. Modma already wrote that correctly, the price is ridiculous and twice as high as Vast.
Aside from the increased price, the biggest joke of it all is:
Direct connection to the machines using RDP on a Windows system.
Who would voluntarily want connect without using SSH but instead use the far less secure RDP protocol? Anyone who works with batches or has implemented automation will not be happy with Windows on this puzzle solving task. But I don't want to spark an OS flame, this just reflects my opinion. Everyone as they like. In any case, for me this is clearly an uninteresting if not dubious offer.
An offer of 100 x RTX 4090 for $500 / day would be interesting, but unfortunately I don't read anything about that