Value is a relative word.
Is there more value today than 5 days in advance of the opener - yes.
There is also the aforementioned “time element” as well as simply not knowing who will be where - injuries or many other factors.
Your already betting into a market that accounts for this unpredictability - unless you are betting with an established book and have the bankroll that a large futures wager will not present a potentially lost opportunity during the next 11 months / futures probably aren’t the best play.
For professional bettors they are a must hold - but most of us here aren’t pro’s. For the recreational fan of a team - might as well get you futures in now as price is unlikely to be higher before the pre season starts.