Because it arrives as a conversation. A client asks for something small, somebody agrees to it in a meeting, and it enters the work without a decision being recorded anywhere.
By the fifth small thing the project is a fortnight behind and margin has gone. Nobody can point at the moment it happened, so the conversation with the client never takes place.
A change request is raised against the project. Its effect on the plan is calculated — which phases move, who becomes overcommitted, what the delivery date becomes — and it is priced at the contract rate.
The client approves it through the portal, and only then does it enter the plan.
It will not stop you absorbing a change. Sometimes that is the right commercial call — the path records it as a decision with a value attached rather than as an accident.
It also will not price a change you have not scoped.
The client sees the trade-off while it is still a choice. Most reasonable clients accept that more work costs more; what they object to is being told after the fact.
Margin stops being eroded invisibly, and the project's history shows what was agreed and when.
Yes, under a threshold you set, still recorded.
That is the auditable route; approval elsewhere can be recorded manually.
Yes, before you send the price.
We will run it end to end on your own numbers in half an hour, and tell you honestly which parts Treepie does not improve.