Hi!! I can provide my own opinion regarding its worth. However, it is my own opinion and may differ from other's point of view =p

1) The option to steal in mine can definitely help players in the beginning as you can earn quite a lot of iron ore from doing so, which allows you to forge. As you know, regular forging requires a wait time of 24 hours for the next reforge unless you have Jonin Medal to refresh once per day. Stealing does cost more coupons each time, increasing by increments of 10 coupons. So I would recommend only stealing once unless you need more. It will increase to a maximum of 50 coupon cost per steal (5th steal and onwards). There does not seem to be a limit to the number of steals but it is unwise to continue to steal once it hits the maximum, unless you have the funds to support it =p

2) Blueprints are definitely worth buying for F2P as it allows them to obtain either A or S treasures through advanced forging. However with every aspect of this game, players c*so be patient and use the regular forging method at a chance to obtain B, A, or S treasure. I personally recommend doing at least one Advanced forge as it provides quite a good benefit at the cost of 136 coupons/ingots for the blueprint.

3) based on my experience, steal would put you against an unknown player whereby you "steal" their ores. At the moment, it does not seem to have an adverse effect on any other player. I will definitely ask and see if I can find out more. Sometimes you will even fight yourself, but you do not lose ores in that case.

4) With every other game, you can choose to spend or gather them through time. It is really up to you!

Hope that helps!

~Jib