Why would he recommend silicon rather than glue in this situation? No Nails is an adaptable adhesive that could stick 'Solvite Man' to a board and fly him round the houses.
I may be miss-remembering. It might be the case he recommended silicone for the biscuits when I asked for advice about extending the width of a worktop when a customer built a side extension and wanted me to marry up the old and new iroko worktops where the old side window used to be.