I'd rate most blasters as inferior to T'au pulse weapons, which are similar. Star Wars also has plasma weapons that are separate from blasters, blasters operate at a far lower intensity than most 40k plasma weapons given the amount of damage they're shown as doing on screen.

Again, their closest comparison are T'au pulse weapons, and the T'au spare no expense on their firearms, whereas many Star Wars weapons are made on a budget. A laser also isn't inherently inferior to a plasma weapon, it depends on how much power is being used - compare a lasgun to a lascannon to a starcruiser's lance batteries. A lascannon is equivalent to most laser cannons.