Mr. Finch is partly right, but WAY out of context as to the question at hand. For example, the 3mb at close distance (10-20 ft) has been gone for nearly 10 years. Yes, 10 years.
From BT 3.0 and up, the throughput is 25mbps (faster than 90% of wired connections) and range of 100 meters (or up to 350 ft). Be careful what you post, brother. 4.0 is "LE" (low energy) and mostly the same as 3.0 which has been around for about 7 years or so. My old iPhone 3G could hold a bluetooth connection and feed a laptop with data 100 yards away in 2008.
Long story short? ALWAYS tether with Bluetooth. The range is equal to WiFi. The power consumption is less than half. The throughput exceeds all but the best LTE connections we have at this moment.
Side note: Bluetooth is now (and has for a few years been classified under 802.11 (WiFi). USE IT.
Last note: Bluetooth REQUIRES pairing a PIN on two devices simultaneously (once and done). WiFi does not. Whomever says BT is not secure is purely out of their brain.