Merchandise and Toys can be Interchangeable with one another depending on the brand/item
In the case of transformers franchise.

I define the toy
As a the main item being focused on which is ethier the playable representation of a character or/and alternate mode that may transform or not transform made by Takara-Tomy and Hasbro.

I define merchandise
as sometime not considered as the main item not being focused on in this case the toy and licenced by Hasbro and Takara=Tomy

With this being said my personal preference is i do not get any toy that dose not transform which is the point of the theme of Transformers but, i might buy merchandise like a mug with an autobot logo