Combinations of tokens get encoded, so if the feature isn't part of the information being carried forward into the network as it models the information in the corpus, the feature isn't modeled well, or at all. The consequence of having many character tokens is that the relevance of individual characters is lost, and you have to explicitly elicit the information. Models know that words have individual characters, but "strawberry" isn't encoded as a sequence of letters, it's encoded as an individual feature of the tokenizer embedding.
Other forms of tokenizing have other tradeoffs. The trend lately is to increase tokenizer dictionary scope, up to 128k in Llama3 from 50k in gpt-3. The more tokens, the more nuanced individual embedding features in that layer can be before downstream modeling.
Tokens inherently constrain how the notion of individual letters are modeled in the context of everything an LLM learns. In a vast majority of cases, the letters don't matter, so the features don't get mapped and carried downstream of the tokenizer.