None (AFAIK) 
… At least, it will give you the same result …
The chaining method used here 
thisTable.find(thisRow) is just another way of writing this : find(thisRow,thisTable) .
The big advantage for me of chaining is readability (especially later, when you get back to a doc you didn’t open for a while). Plus, it simply feels more logical and natural
In this case, this is simply because that’s what Find() outputs/returns : a position as a number …
So, in other words, with this formula:
thisTable.find(thisRow)
You actually get as a result the position of thisRow in the table (which different than the RowID set on Coda’s side)
Well, a table is just a list of rows and each row in a table has a Reference which is always the value from your Display column. (The display column always exist in a table, it can’t be avoided… Even if you have only one field (as by default, this would be the Display column))
The Reference of a row is that specific value allowing you to access all the other values stored in the various fields of your table for that specific row …
When you use thisRow alone (as in thisTable.find(thisRow)), you get the reference of this row in a table.
Now, if you chain it with something else :
E.g.: thisRow.Name
You’re actually accessing the value stored in the field Name for this specific row (which is here a text value)
The explanations here might not cover everything about the subject though
Add-on: This video from the Great Wizard @Paul_Danyliuk might interest you (generally speaking )