Here is how I see it, I'm not saying it's right
You can lift 150kg (it's an example, don't get your panties in a bunch bruv) but 155kg and your grip limits you.
You use straps for a while and get to 160kg strapped
You then go back and lift 155kg without straps, presto, progress!
Then if the plateau is over for the time being, you continue strapless. If not you can try other methods (accessory work etc) or continue straps for a while.
Using straps isn't a slight against the achievement it's a tool to be used when appropriate