There are many differences between personal statement writers and academic writing services as well as being several similarities. For a start, the subject matter of the two is quite different; the personal statement can be used during applications, for example, to university or college; whereas, academic writing is more concerned with writing essays, dissertations and thesis writing.
That isn't to say that there is no overlap between the two. They may be quite different in the style of writing, however, both still require a high competency when it comes to writing. Therefore, both of them share a certain amount of skill, without which, the quality of the work produced would not be to a very high standard.
A quick search online finds many services that offer you personal statement writers or academic writing, or even the two combined. Because of this overlap of skills, it is entirely possible that an academic writing service may also write personal statements -and vice versa -although they may not necessarily use the same writers for both.
So, basically they both require a good standard of writing and can both affect one's academic life in one way or another; either in which direction it progresses or how well that progression is. There are writers that specialising in either one of the other, then there are also writers that are highly skilled in a range of writing and able to offer an equally good service whatever the writing they do. What is important though, is if you are thinking about hiring someone to help you with either of these different kinds of writing, is that you hire someone that is highly skilled and reliable.