Semitailless1 swept-wing aircraft without active stability enhancement2 generally3 have extremely poor handling characteristics, most notably a tendency towards violent pitch oscillations at high subsonic mach numbers, and yaw and roll oscillations at mach numbers slightly beyond this. As a result, while the swept-wing semitailless layout was briefly quite popular for transonic and supersonic aircraft in the late 1940s and early 1950s (witness, among others, the DH 108, X-4, and F7U), it was quickly abandoned, only making a comeback much (much) later, with the advent of computerised active-stability-enhancement systems.
In the meantime, supersonic aircraft near-universally switched over to delta-winged layouts, which worked just as well for supersonic flight and had none of the nasty quirks of semitailless-swept-winged layouts. This despite the two layouts being extremely similar; indeed, a semitailless swept-wing aircraft can be seen as a delta-winged aircraft with part of the inboard trailing edge cropped out:
Why do two such similar layouts have such different handling characteristics?
1: Aircraft that do not have a separate horizontal tail, but do have a vertical tail.
2: A system where a computer constantly monitors what the aircraft is doing and continually makes tiny flight-control inputs to keep it doing what it's supposed to.