The advantage of Bluetooth is that it runs on every smartphone out there. There is quite some incentive to have the basics right. This can not be said about chips that are not present on smartphones. I'm not saying that Bluetooth cannot be hacked, before 4.2 they didn't use proper key exchange, so e.g. you could use Ubertooth (https://www.sparkfun.com/products/10573) to capture the exchange. However, with Elliptic curve Diffie–Hellman it became pretty standard. The requirements from Apple for HomeKit are even so ridiculously high that your gadgets might be safer than your bank account.

My bet is that indoor positioning is gonna be the game changer in the coming years (not robotics, not AI, not voice recognition, not yet, at least). So, I'm particularly looking forwards to see what's in store on the Bluetooth roadmap in that respect. The only thing I wish is that they would be faster in rolling out mesh functionality...