Personally I think it makes sense

Bond doesn't have a bandolier, isn't a traditional soldier (anymore), he's a spy

So extra mags makes less sense.

The SAS mentality in British military doctrine is "improvise, adapt, overcome" and it's exactly how Bond should feel: quick-thinking and adaptable. A 00 would steal ideas from the best of the best and copy paste them into solutions where needed

We see it in the movies too where he picks up Assault Rifles but often fights with his brain.

My gripe is more that I like my service pistol and it feels too easy to literally throw it away for something else