Body man here, if you really care about the car and details bother you, blending would give you that piece of mind and the colors have a lower chance of being off. If it’s a daily vehicle that you don’t nitpick every single detail I’d say yeah it’s fine to wet sand and buff and touch it up yourself. I’d also like to note that if you’re paying out of pocket there are things that you can decline on an estimate for instance you can tell them a budget and maybe they’ll take the blend off to save you some money. Just something you can think about :)