I put 100$ a while ago, only because it should speed up aquisition after the wipe (they'll return the gems), but I don't intend to spend any more.
Like I've said before, I excluded green in general and for the most part, have most of the playable cards in the pool from the other colours.
The new WC wheel is nice because you have a notion of how long it will take to get the cards you need. For example, I wanted 4 gilded lotuses. I had 0. I got 1 random rare WC, another from the wheel and happened to have 6k gold to get another by opening packs, so I went for it, got another random rare WC and now I have 4 lotuses.
Right now, I'm having fun with jank, so blowing WCs on dubious cards is fine.
Standard meta is at a point were people are looking for the next big thing after rotation. Sure, that'll only be answered when the new set arrives and kaladesh and amonkhet are gone, but there is room for brewing ATM.
I don't play everyday, but that's fine too because most of the gold comes from quests you can do every 2 or 3 days anyway.
Also, the new player experience has some pre-built decks you can unlock by doing some quests and they have some playable cards (including dual lands), which is a pleasant help in building a collection.
Worth playing?
I guess so, it's probably the best online mtg experience you can get and it's certainly entertaining enough.
I did similar. I put $100 on the game, spent about $50 of that on packs, and I'm just burning through the rest on draft. They say it'll get reimbursed as gems when it wipes, so I didn't see any big downside.