An undo-tree-based solution has the same issue as the other undo-based approaches already discussed in this thread.
When multiple edits have been made to the buffer since the target text was deleted, any undo-based solution would reverse those edits before restoring the deleted text.
The yank-from-kill-ring command provides a straightforward way to retrieve and reinsert the deleted text into the buffer without undoing numerous legitimate edits made after the deletion.