If it is already nearly end of the month (>16th) then I don’t recommend buying it for now, but if it is early then buy it if you wish. I still think the builder packs you start out with in TH2 is more worth it than the season pass, because those are long term upgrades while the season pass lasts only a month. Think long and hard whether you want to spend the money on this game.
With just $5/month, you can earn $200-300 worth of value per month. Now that you’ve reached TH7, you unlock one of the greatest things in this game, which is the season challenge.