Should I use form to submit JSON data to REST api

Is it approved to use a html form to build interface to collect user data, convert it to domain model in front end and POST it to server using JSON?

I like to think the user input part as a logical form, event though the server expects JSON. For user it is all the same, so why not just to use a form to collect the data and implement a custom onSubmit method? Another option would be use detached input fields and buttons.

Is this considered a good practice to use forms for JSON POST and what are the good and bad consequences of this practice?