I'm a native Hebrew speaker, where we have wild word morphology, and also worked on NLP at a large bank where we trained models to anlyze Bloomberg chats (that are almost english but behave like a DSL).
In both cases, "token-free" has been the way to go for extractive tasks like entity recognition.
It's unfortunately a technique that is off the beaten path, so a lot of extra engineering effort needs to be paid down. For example, when dealing with spans but embedding the text at the byte level, one needs to account for multi-byte codepoints that can throw off the alignment between "encoded" and raw bytes.
As the article alludes, the increase in sequence length can be very expensive. In extractive tasks, I've found it effective to use much lighter models with limited (but large) context length like ByteNet[0].
Thinking out loud, as always, there is no one-tool for everything. Often the summarization/few-shot capabilities of an off-the-shelf transformer are so far ahead that it's not worth building a model from ±scratch to solve the subtlties of tokenization. Other times, you don't need the unbounded context or have a simpler task and can forgo the power of off-the-shelf models for the specificity of a token free one.
[0] Neural Machine Translation in Linear Time (https://arxiv.org/abs/1610.10099)