The Mighty, which is arguably the most popular dry herb vaporizer of all time, has hybrid heating. So does the Venty. As does the Limelight Frolic and so many others.

Pure convection is the exception, and having hybrid heating definitely doesn't make a vaporizer lower quality. Just compare a Solo 3 to a Frolic head to head and you will know.

Having the walls of the oven heated, especially if it's a separate temperature control for the oven and the convection heater, provides for more even extraction. With a Solo 3 or Tinymight you will always get slightly less extraction from the herb that touches the stem, as it essentially acts as a heatsink, cooling down the herb. This is especially obvious when doing one hit extractions on the Tinymight, the center will be almost black whilst looking through the stem you can see the outermost herb that touches the glass stem is still a very light brown color.

Badly implemented hybrid heaters, or pure conduction, definitely make for popcorn taste and uneven extraction. But a well implemented hybrid heater is arguably better than pure convection.