It’s unhealthy to carry them in modern backpacks id say. Poor design in a lot of them helps contribute to back problems
I absolutely refuse to buy a backpack without a hip belt of some sort, because while you might not really need it for the five-minute walk from the bus stop or train station to the office, that changes when you're carrying it for a two-hour walk in the snow.
Thank you for the tip btw I am soon in the market for a backpack and will take care to get a good chest strap