Plastic drinking straws are better than wooden dowels [and obviously paper straws] any day.
The hollow cylinder [a straw] is much more stable and capable of withstanding more pressure than a solid cylinder [a skinny wooden stick/dowel]. This is not an opinion, it's a physical fact.
A wood dowel has, essentially, a single point of contact on the board and displaces cake when inserted. A straw has multiple points of contact going around the entire O and it does NOT displace cake, but instead finds itself better stabilized by the cake that winds up inside of it when inserted. And, you only use half as many straws as dowels for support.
The weight, or size of a tiers, has no bearing on how well straws will support a cake. If the # is correct and they're cut straight, they'll hold. They CANNOT be crushed or bent vertically and it's difficult for them to shift. Wooden dowels can slip & shift in a damp, greasy environment and extreme downward pressure can cause them to bend.
My only use for a wooden "dowel" in my cakes is if a stacked cake will be traveling some distance for delivery. Only then do I insert a single, sharpened spike all the way thru a 2 tier cake and 3+ tiers gets 2 spikes. I NEVER use skinny sticks to support cake tiers.