It will do more than that though I think?
If May is directed to renegotiate the WA and the EU refuses to do so (as everyone knows they will) then politics of what is acceptable back in the UK shifts somewhat? As in with each option (even false one) that gets rejected another (like May's deal, for example) becomes more politically palatable to some?
That is in fact true, but not May's intention here - she looks to be resigned to 'no deal' now and the passing of the Brady amendment this evening will simply help her manage it (in terms of her own reputational damage).
Other options, like a general election/2nd referendum/revoking A50 might start to look more palatable to some, though (obviously none carry anything like a majority at this stage), given that the only alternative will be no deal.
Presumably extending A50 would still be an option too?
That can't be done unilaterally, though, and the EU would only agree to it if there was a GE/2nd vote on the table (or to allow time to pass the legislation for a ratified WA).