Merged cells are not supported in OneNote's native tables.
And WordNote is a Word-based plugin note.
The Word table itself supports merging cells. So, merging cells is also natural supported in WordNote.

In Windows Office OneNote, you can open an attachment in page, and then save it back to the page after you edit it.
But, in OneNote for Windows 10, attachments in the page cannot be edited and saved back to the page. Attachments can only be viewed in a read-only mode.
 
In WordNote, you can open the attachment on the page to edit it, and then save it back to the page.

Browse native PDF attachment in WordNote, and annotate the PDF with comment of Office Word.

Office Word 365 or Word 2019 supports handwriting and drawing.

Similar to OneNote, WordNote also provides To-Do items.  
To-Do list is a list of tasks that need to be completed, typically organized in order of priority.

WordNote provides read mode that prevents change content when reading

Similar to OneNote, WordNote also provides support for internal links, including links to folders (like OneNote sections), pages and paragraphs.

WordNote adds features like Office OneNote, based on office Word.
WordNote is a non-cloud alternatives to OneNote.

Rename or delete page in WordNote. Can be recovered from the Windows Recycle Bin.

We can encrypt the page in WordNote by using Word's Document Encryption feature, and protect the document with a password.
 
If, every time you use the same password to encrypt the documents, you can use the "Document Password" menu in WordNote, enter the password, and view all the encrypted pages at once without having to repeat input the password multiple times.