The trick is to avoid doing it regularly or you start getting 'mentally addicted'. I cannot even contemplate working under the influence of THC. And reading anything is pretty much impossible unless it is a very interesting novel or a magazine. It will take you about half an hour to go through a page anyway.
And as I have said before , it depends on your personality as well. I have never felt addicted to it to be honest. Yes , you do look forward to smoking on the weekend but its the same as looking forward to doing anything else you like doing.
If you have loads of money and don't need to work then you can happily smoke it everyday.
But the above applies to any drug to be honest(Exception being some stimulant class drugs). I doubt i would be very productive under the influence of alcohol as well. And don't think I will be progressing much career wise if i turned up to work drunk everyday(Unless you are god aka Paul McGrath).
Generally , I have seen all the arguments against weed can be applied to Alcohol as well. Unfair that one is legal and one is not.