In politics, partial victories can snowball. And vice versa: repeated loss teaches helplessness. The direct real effect of this would be small, but I'd expect it to be much more useful than a loss.
Added: If you read about Watergate, the scandal wasn't any one event or one reaction: it took over two years from the break-in to the resignation, and people weren't sitting still. Some of the important action was in Congress. (Admittedly it was a different country then.)
This isn't Watergate. There isn't widespread public outrage. If you want to change the policies, you'll need to generate or simulate that outrage first.
I was politically aware at the time, it was more than a ripple---burglary of the DNC headquarters meant something---but it wasn't big for a long time, and even longer before it became bipartisan.
This is the very first (recorded) vote on the issue; even if it were 100% symbolic, which way it goes, how many votes for it will make a difference going forward. And this is bipartisan from the beginning: in a Republican House, an heretofore obscure Republican is the sponsor with the very prominent Democrat John Conyers as the leading co-sponsor.
Added: If you read about Watergate, the scandal wasn't any one event or one reaction: it took over two years from the break-in to the resignation, and people weren't sitting still. Some of the important action was in Congress. (Admittedly it was a different country then.)