Would you hire the fox to guard the hen house? Even if using the seller's agent might save you a few bucks (it won't), there is a lot more to the home buying process (yes, it's a process) than offering X and having the seller say "OK". that's only the beginning

Every home sale is a negotiation of dozens (if you're lucky) or more (if you're not) conditions, contingencies and possibilities, both on your side and the seller's side. You need someone whose fiduciary (that means looking out for your money) is to you and not the person on the other side of the negotiations.

What turns up on your home inspection?  "This is the finest home we've ever seen.  There is absolutely nothing amiss anywhere. Every system and appliance works perfectly".  Never happens.
How do you decide what to ask the seller to repair (or credit you for the cost of repairs so you can get it done yourself).  Ask for every single thing on the average home inspection and you will most likely anger the seller so that, at the very least subsequent negotiations are very difficult, and you may just have the seller tell you to go away. 

It's a process.  It's a process.  It's a process.  Am I getting through?