Valuation wise they’re arguably doing that since Amtrak points are worth 2.5-2.9c towards travel (though granted since you can’t redeem for saver fares the real value is somewhat less than that). As for the other benefits you mention…companion tickets and one class upgrade certificates (albeit not for sleepers) are already annual benefits of the card.
Originally Posted by www.amtrak.com/apply
Complimentary Companion Coupon
Get a complimentary Companion Coupon upon account opening and each year when you renew your card membershipComplimentary One-Class Upgrade
Get a One-Class Upgrade upon account opening and each year when you renew your card membership for an enhanced travel experience