Depends on whether or not Ledger or any other company would every actually need to "contact you about your order". I think most people give out their phone number far more often than they realize. For the sake of $5 for a prepaid SIM which I change every 6 months or so, a disposable phone number I don't care about and can hand out freely is great. I maintains my privacy, I know I'll never get phished or scammed via my real phone, and completely eliminates my concern regarding database breaches like this.
I've never had a legitimate contact via phone regarding an order except a few times someone left a message saying "you'll need to sign for a package tomorrow", which may or may not have been legitimate, and a couple of times shady sites tried to upsell me because they magically ran out of that awesome deal that was too good to be true to begin with. I think I would be fine with the order cancelled if there is a genuine problem and they can't reach me.
Now if I have a disposable phone that I'll never pick up and won't carry with me and probably won't even keep it charged, what's the point? And I wouldn't be so bold to claim that I'd never get scammed on my real number. If I give it to kid's school or doctor's office - legitimate places to give my real number to, right? - and they get hacked I'd be in the same position as with Ledger now, just perhaps with more false sense of security.
Even a friend or a relative losing their phone with my number in their contacts is a risk - impersonation scams are rampant.