1) The "punishment" for rushing conquest to completion was having to wait until the event ended to collect the rewards, knowing that other players might well be earning the same prize box without spending crystals.
2) Just why do you care how long it takes me to complete the event once you set the clock? What are you, my foreman? THIS IS A PHONE GAME CG, NOT A SHIFT JOB AT A FACTORY. This is some ridiculous reasoning.
3) The only consumables I ever used was a speed booster (once, I think) and some stamina boosters when I was impatient to complete a certain battle/feat now instead of waiting for stamina to refresh. I expect I'll be able to continue to ignore all other boosters/consumables. If you make conquest unplayable without them (forcing players to spend resources on them) that's very garbage of you.
Start date on the 30th, I look forward to it being cancelled on the 31st because a bug will be discovered that makes JKL eligible for DS GeoTB fleet CMs as the Fleet Commander of the Executor or whatever, and then not seeing Conquest 8 until March 2021.