There is a rule in using comma in a phrase e.g "as well as"
Please proofread for spelling mistakes, as well as grammatical errors.(This sentence doesn’t require a comma). yes this is just stating both like thge word "and" or aother word used to connect a list, or sentences.
Spelling mistakes, as well as grammatical errors, are distracting to a reader. ( This sentence does require the commas around the non-restrictive clause). This "as well as" adds information that you don't really need to stick in there but as extra.
Examples not using as well as (maybe known as something eles as I can't remember completely)
I, myself love candy.- The myself is added for emphasis and is extra information.
You, the fifth grade reader, will love this book about an adventurous and inquisitive journeyman.- it is telling more about you the reader they are focusing on.