If I didn't have a thermopen first, I would probably agree with you.
However, I just bought the wifey one of these from Thermoworks a week ago.
(Yes, tired of her looking for, using, then hiding my thermapen)...
It measures as fast as you think a $19 thermometer does.
It says up to 6 seconds. After using my Thermapen, that feels like double that.
Bite the bullet, get a thermapen.
Use a junk email address and sign up for their newsletter.
You'll get put in a monthly drawing for a free one, and you'll get emails on specials they run (like the recent $74 open box sell off).
You can by a competitor...or you can buy the real thing.
It's the best BBQ tool I've ever purchased.