This may be a difficult question to answer but I'm curious as to the reason for this.
película in Spanish is
pe-LEE-cu-la. It has an accent to mark how to say the word.
peninsula in English is pronounced
pen-IN-su-la. But it doesn't have an accent mark. It seems like we simply learn how to pronounce this word at one point in our lives, and then from then on out, the written word reminds us of the pronunciation. (I don't think the pronunciation is inherent in the way the word is spelled, similar to how
horse are pronounced differently, or
tear has multiple pronunciations for different meanings).
It seems like accents are a bit repetitive. It seems that you could just put together a dictionary of pronunciations, and then learn the word pronunciation once from the dictionary, and then this makes the writing a little easier, since you can omit the accent.
Then the idea of a written word is simply a helper or tool to invoke a memory of the pronunciation. You already have to remember the definition of the word (it's not like the definition is written next to every word you read). Likewise, the accent marks can be omitted.
The only reason I can see accent marks being useful is when it is not your first language and you need that extra help all the time to remember how to say things. Or perhaps the accent marks like in Spanish serve to standardize how the population speaks. I'm not sure. Wonder what the history of accent marks was in Latin. They seem to have a lot, but maybe that evolved and there is some history to it. Anyway, that's probably a separate question.