There are workarounds (e.g. the key is also the dongle, like with many cars) but for the sake of this argument, yes, you'd need to carry both.
The car analogy is a good one, actually, because keyless entry has become commonplace in that arena. It's less secure, but so darned convenient. These days, it has become nearly impossible to get a mid-tier, or better, automobile without keyless entry; though it won't happen as quickly, we can expect the same trend with our home door locks. After that, we'll be replacing our locks every 4-6 years, or at around 150,000 miles. Yey, more stuff to go obsolete and throw away!
Generally speaking, the privacy and security concerns that industry continues to ignore are turning me into a Luddite, so I won't be in line for an off-the-shelf IoT device anytime soon, if ever.
