As long as you have life to spare, Fountainport can be a repeatable way to create threats and draw cards to overwhelm your opponent
(Track metagame pages and recent events on Inkdecks.) (inkdecks.com) Gameplay Examples Steel Aggro Curve - Amber/Steel Style T2 Nala
In general, when looking at power level, I considered the overall game plan, the synergy of the 99 with that game plan, things like interaction, ramp, mana base and card draw, the commander, and the power of the remaining stand-alone cards
This process can be costly, but it is worth it if you think your card could be worth a lot of money in the future
Unfortunately, at full speed of four, this card draw can wipe you out quickly but you've likely got enough firepower in your hand to end the game way before that