I got one love emojis and think it was one of the best decisions to include them in Unicode.
I don't buy that you can have tens of thousands of weird human scripts but then a few icons representing non verbal communication is suddenly "too much". Sure a system might not support everything but the same is true for the regular text scripts. And then it means I can include emojis in my she'll script, slack messages, copy paste around, and it just works.
If the lower upfront cost is the only thing you want then there's no need for a subscription. Just have a financing option like businesses have been doing for decades. And if the person stops paying send it to sent recovery. It's a solved problem for a very long time.
The only reason why you would want a subscription is to keep charging people even after they have paid the full price and interests, which is a super annoying and bad policy to have in the first place.