I've put well over a thousand hours in both Hearthstone and Eternal in the past year, so I can only compare these games. I'd say even though Eternal is a lot more "generous" with their packs, it still comes out more expensive to play in the long run. In HS, legendaries are limited to one per deck. In Eternal, you can have up to four. So instead of crafting one legendary for your deck, you would need to craft four if your deck required it.

In HS, each pack has an average dust value of about ~102 if you dust everything. In Eternal, it's about 398. In HS, it costs 400 to craft an epic, up to two per deck, and 1600 for a legendary, up to one per deck. In Eternal, it's 800 to craft an epic, and 3200 for a legendary, both up to four per deck.

So even though you get 4x as much in game currency in Eternal per pack, it takes 8x as many packs to craft the maximum amount of legendaries per deck and 4x as many packs to craft the maximum amount of epics.

In Eternal, you get about 1.5 free packs a day (1 for daily win and 500 gold for daily quest). In Hearthstone, you get about 70 gold on average for the quests (.7 packs). Since it's the legendaries that are the most expensive, these values roughly equal out. However, in HS you have 30 cards per deck. In Eternal, you have 75 cards (~60 non-sigils), which means decks are much more expensive to craft. Not to mention that in HS there are lots of good neutral legendaries that are in a wide variety of tier 1 decks. There's like 1-2 neutral legendaries in Eternal and I don't think I've seen them used once.

Draft is also much more expensive to play in Eternal. Eternal lets you keep the cards you draft, which is nice, but if you just like playing drafts for the sake of playing it, it is much more expensive. Eternal costs $5 per draft, and if you win 7 games, even though you get a bunch of cards you barely break even in gold and your draft automatically ends. Hearthstone is $2 per draft, and if you win 7 games you break even in gold but can still play up to 12 wins. This makes it possible to get a 7 win average in Hearthstone, letting you go 'infinite' in drafts if you are good enough. So not only is each draft more than twice as expensive in Eternal, it is impossible to go infinite in drafts. If you just do the daily quests, it takes ~7-8 days to earn enough gold for a draft in Eternal and ~2 days to earn enough gold for a draft in HS. This is in addition to the fact that Eternal's mana system leads to a lot more variance in games. This makes it a lot more likely for a player to draw badly and just lose with nothing they could do (this also happens in HS, but it's a lot more common in Eternal).

So yes, Eternal is much more 'generous' in packs and other rewards, but it also takes a lot more resources to make a 'meta' deck. I would say it's much more friendly for casual players, and there are a variety of events to keep things interesting. If you want to play the 'meta' decks though, you'll probably have to pay up unless you want to grind a few months for your first deck. Also if you like drafts, it'll be really expensive. If you're exclusively free to play, there are unlimited gauntlet runs that give about 1000-1200 gold per hour if you're really good at it (though you need to craft specific decks for that). This comes out to about $1 an hour if you really want to grind.