I've been trying to understand Safaricom with their recent products in the voice/SMS/data segment, and I can only say they have a Nokia or Samsung approach to things. Throw everything to the wall and see what sticks.
If you remember Nokia, pre-Windows days, they'd release so many devices in so many segments, sometimes devices overlapping in same segments, all in the name of providing options for everyone. One would argue it won them the leading smartphone company of that time.
Samsung took this same approach threw everything into the Galaxy, they sort of came back to consolidating device categories, the structures are a bit easier to read now.
Then there is Safaricom. It started with them being rattled by Airtel with Unliminet, and they did poach that office to work on their next products, came up with Blaze youth product, a model that's an 'innovation' of Frank by OCBC from Singapore, something that CBA has perfected (story for another day), they also came up with Flex, a product targeted at an older demo, I am not sure it went the way they wanted though. Then there is Tunukiwa bundles, something that if I understand correctly is an algorithm based bundling product that bases the offers Safaricom offers you for bundled prices on how you consume their products. If you use more data, less SMS they will try to package more data bundles, more SMS for a certain price.
Now this brings one thing. It's possible for one to be on Blaze, then subscribe to the Safaricom daily bundles, that have SMS and data, and Tunukiwa daily bundles, that could have SMS and data. It's also possible to be on Flex and subscribe to these same options. Remember Blaze does give you custom options on what you prefer spending your money on, whether voice, SMS or data. Flex does the same, in a different way though. Safaricom Advantage users get their own version as well. Pay at the start of the month for a certain number of SMS, voice minutes and data.
If you have no plan as well, you get the options of complete free range, get airtime minutes raw, purchase data bundles in their raw form as well, or get into either Tunukiwa or Daily bundles. All these options are available across the board. And unless you opt out of their promotional text messages, you will most probably be reminded of each one of these options regularly.
Throw everything to the wall, see which sticks.