My understanding is the MFi program for getting devices approved for the Apple ecosystem is non-trivial. (Any effort being more than the zero certification needed for Android accessories,but I'm biased)
MFi certification is a bit of a headache, yes; you need to buy a special encryption chip (or license and implement the encryption), and you need to write your communication protocol atop Apple's External Accessory framework. However, MFi is only required for custom Bluetooth Classic profiles, or something physically connecting to the Lightning connector. Worse still, you have to implement your protocol twice or else forego Android support when using MFi-secured Bluetooth, since Android doesn't know how to speak EAAccessory.
(Standard Bluetooth classic profiles, like A2DP for audio or HID for a wireless keyboard, don't require MFi; this is why wireless headphones, which speak A2DP, work on both iOS and Android without needing MFi functionality, or why handsfree and Bluetooth audio streaming work fine in cars with both iOS and Android.)
Conversely, Bluetooth Low Energy (BLE)—also known as Bluetooth Smart—does not require MFi certification. This is a large part of why BLE has seen such wide adoption over the past few years, purely aside from the low-power benefits: there's no additional certification needed to write software for it on anything, and you can use the same protocol on both iOS and Android.
It's worth noting that BLE, despite the name, is wildly different than classic Bluetooth; think of it like TCP and UDP, where both are built atop IP but they have significant differences. BLE is great for things that are connected for a long time (fitness wearables, smartwatches, etc.) where you don't want to eat a lot of battery life over the lifetime of that connection, but you definitely wouldn't want to try to use BLE for streaming audio because the bandwidth is kind of terrible.
Mind you, this isn't to say that a BLE implementation of Summon might not still be an improvement over a trip across the Internet if the car (acting as peripheral) negotiated a sufficiently small connection interval with the phone.