This monster card also has a lot of effects that prevent it from being easily countered, and if your opponent does manage to destroy this beast, then it has a built-in failsafe that allows a special summoning of another Flower Cardian card from your Extra deck
For the portion of your money that needs to be accessible, safe, and earning something predictable, a different approach makes sense
At the start of the anime, this card is considered extremely rare and only four existed (the fourth being the one that Kaiba destroyed himself), but in real-life Blue-Eyes is anything but
[C] Rule of Evil
If Uncharted Haven is somehow on the battlefield without a chosen color, its mana ability won't add any mana
The small number of cards required to make this combo work make it possible to run this single-card engine in multiple different decks as a way of bringing extra effect negation to your play to slow your opponent down