>Making Apple products work well with other Apple products isn't lock-in.
Cool. iMessage works perfectly well with SMS, which is the only true open messaging standard, and therefore will work with anything else that interoperates with SMS. Job done.
Cool. iMessage works perfectly well with SMS, which is the only true open messaging standard, and therefore will work with anything else that interoperates with SMS. Job done.
Come on. Apple's VP of software engineering would not be debating Android support in internal emails if SMS worked "perfectly well".
Most of the iMessage features, text, video, pictures and "reactions/tap backs" work over SMS. The only real feature missing is delivery and read receipts but most people in my experience have read receipts turned off. Apps also don't work but I've yet to see someone actually use that feature.
Other than 'text', none of those things use SMS:
Sending pictures and videos uses MMS, which is one of the most flakiest parts of the old feature-phone ecosystem because it's inextricably tied to the level of support from both the sender's carrier and the receiver's carrier for particular MMS message content - and how carriers love to charge insane $-per-byte for SMS/MMS content. While in the US exchanging video MMS between the 4 (or 3...) major carriers you likely won't experience any problems provided the video is under a few megabytes and using a well-supported codec like H.263/H.264, if you see what it's like for the rest of the world (Europe, India, etc) you'll understand why services like WhatsApp are so popular: because carrier SMS/MMS service is awful... if not obscenely expensive.
The "reactions" thing you mention, to my knowledge, is not supported by SMS either - it's either an Android-specific MMS extension or you're using RCS - and Apple has no incentive to support RCS, excepting any kind of laws requiring phone carriers and handsets to fully support RCS (I wish...) in order to be sold in a giving region.
So iMessage app doesn't work like SMS reading app. It forces you into using iMessage account to just read an SMS. Later it lures you into using iMessage instead of SMS to make it harder to switch to another OS later.