First up, let me apologise for the slightly click-baity title ;-)
Yeah... it's definitely going to be worth it. The cards bought back in Alpha/Beta are now worth 10X - 100X.
Me Personally: I spent a few bucks on packs and cards, and even without selling them will recoup the original costs in a few days/weeks with just the SPS airdrop, and then there's the on-going DEC daily income from renting them out... so yeah, DEFINITELY "worth" it.
The title was a) to get people to read the post and b) re-evaluate my original $1-A-Day objective without actually spending any money on cards... I'm not entirely convinced that's possible anymore.