Sash windows; Silicon instead of putty?

[Adaptor]

Next door seems to be doing a rather bad glass replacement; looks like silicon seal or adhesive instead of putty . Its a clear gel looking thing put between the inside of the glass and the interior wood. They havent done the outside yet

Is this a valid method in an Edwardian sash?

 

[squowse]

it would be a normal thing to do if glazing with timber beads as well, not on it's own.
i wouldn't use silcone though as it;s not paintable.