Like the video games, a lot of the fun of the Pokmon TCG is the chance to assemble your own party of Pokmon, combining different strengths, weaknesses, evolutions, energy types and trainer cards to gain the advantage over your opponent and ultimately claim victory
I still like that it rewards playing more colours, but even if you're playing 4C control or something, it is hard to get out that many differently coloured permanents, so the flashback actually being worth six mana might be a problem
It's the opposite of flashy, insta-win mechanics like Cascade or Storm
It can be very strong in some matchups and very bad in others, so think a lot about it during sideboarding when you decide to keep or not this card in your deck
Card Kingdom also has an excellent buylist, and its a great tool to browse through and see what you could send their way without having to list everything you own first