In the following example, it remains unclear to me why the term もの is written in hiragana.
Here is a second example, where 優しい is written in hiragana.
- For optical reasons, some kanji are written in hiragana to obtain the desired verse length.
- Hiragana writing is used to let an open interpretation to the reader (for example 物 or 者, whether this is an object or a person)
- Too complex kanji are replaced by hiragana to match the target audience (seems not to be the case here since the above kanji are "simple" ones)
Is one of these suppositions correct? Or is there any general rule for this?