Others explained better about upgrades , its a question of chance and brands , for me its 66% . I often get upgrades , but the thing is i usually come to hotels during low season and/or weekdays

Upgrade offers depends on the brand , i have seen them at pullmann or fairmont but not yet at sofitel .

About OLCI its useless and a waste of paper .

The hotel just receive informations from your ALL profile , and you will still need to provide your ID and sign the form anyway . I think soon i will reach the GM of the hotels where i often stay (not just 2 or 4 times a year) and ask to be exempted

Compare this with hilton where , if you already stayed in a hotel before , you can just check-in online , get your virtual mobile key and dont need to pass by the front desk anymore . Therefore you will easily understand why i am begging accor to give us something Marriott or Hilton started to do long time ago