Bluetooth was never designed to be a long range system. It was designed to work within 30 feet or less between two devices, although some Bluetooth enabled devices can go beyond that since the technology has improved. Bluetooth was not meant to be a replacement for a wireless transmitter/receiver system, like a router or switch that you would use for connecting your laptop/tablet to the Internet, but rather it was designed to enable peripherals like headphones, printers & speakers to work with a base device.
The range quoted by Thermoworks for their thermometer @ 65 feet is an improvement over the original distance specs, but I would go with another wireless thermometer if you are looking for more range than that.
Bluetooth doesn't go through walls very well either. A true wireless thermometer would perform better if you wanted to have a wireless monitor in the house while your thermometer was outside next to your cooker.