8: Each creature target opponent controls phases out
For starters, getting to potentially affect all artifacts in play is a big deal
Battle a few times to master your starter decks strategy, then open the included booster pack to upgrade it with even more powerful cards
Considering that there are ways to Reveillark this (since its a 2/2) and other shenanigans, you can set up all sorts of infinite combos and reanimation loops with the Guide, generating extra mana, death triggers, and more
Its a Reserved List card, remember, so its current retail price of $40 might be more permanent than you might think
You might not think it would do much, but unfortunately there are problems that arise in Magic design when the legend count is too high