I buy crates for the mods, which gives me bonuses for the races, which pays for more than the cost of the crates (each card gets you around 33% credit bonus with three applies and that’s 100% bonus over all uses so each card is worth, on average, the base reward you get from each race - I usually do long races in the career so those get you a decent return, which more than pays for the mod cards).
I’m not sure about just how many of the cars on the roster of 700 are locked so you can’t buy them (directly with standard in-game credits). It seems like this goes way beyond DLC cars (of which there aren’t many and only something like 50 planned as part of the bad value season pass) - that so many of the cars are locked behind the “speciality dealer” or will appear once Forzathon events finally start happening (thanks for releasing Auction House Turn10, now the XB1X version is out and they actually consider it 1.0) or claim to come from loot boxes (which cost far too much for the ones that usually include a car - especially as most of them don’t include the locked cars).
Basically the number of cars that are locked and you can’t buy (ever, directly) are my issue, the levelling of the first five car collection levels seems to happen fast enough (within the first dozen or so hours of the career racing so you’ll have unlocked every car you can buy well before getting half way through the career - that seems like a reasonable way to make the career feel like it has a progression, especially as you can get a few high-tier cars at the start via things like the free first car and event rewards). It seems like that system may be telling people to buy crates to unlock the remaining models but also… I’ve seen people on streams after using a cash glitch to get infinite money and those crates really don’t seem to actually drop those locked cars. So they seem like the false promise of those vehicles.
Looking here at some Tier 5 selection, this (the arrow is a DLC car, the locks are all cars that you can’t ever buy with in-game credits but they claim you can get from crates if you’re not prepared to wait for the weekly “speciality deals” or eventual Forzathon rewards) is not a good way to deal with a roster of lots of cars. Yes, some of them are rewarded at other times in the game but it’s pretty bad that they tell you to buy some crates to unlock them when you try to select them from this catalogue. That’s where I hate the crates idea in the game - that they might be a factor in why so many cars are locked so you can’t buy them with credits. Once I’ve unlocked a tier, I should be able to buy the cars once I’ve got enough credits (unless they’re DLC I haven’t paid for).
That the crates can drop duplicate cars rather than always giving you a new car if you’ve got a gap is indicative of an exploitative gambling design rather than a “fun randomness” design. Hell, even Dota2 crates ensure you complete a collection before dropping dupes and that’s an F2P game. If cars can come from crates then it should give you a car you’ve not got until you’ve completely your collection.