Pocchetino has taken and moulded Spurs into genuine title challengers and CL regulars. He also put together the framework at Southampton that Koeman stepped into and used.
He's understandably looked at by a big club like that. Koeman has done f.a. here or elsewhere for a decade.
He's turned them into CL regulars? - is that by managing to qualify for it once so far mate - thats a really bizarre measurement of regular like.
Koeman inherrited the framework, but one that had been stripped of nearly every decent player - but he rebuilt and improved year on year even given those restroctions - so his time at Saints matches what Pocchetino did at that club mate.
As for Spurs being genuine title contenders - hmmm, they did finish 11 of Leicester last seaosn, but mathemathically at least in the media where trumpeted as the last title rival to fall away, as for this season - theyve never even been in a race mate as Chelsea have had it won since Christmas - unless Christam title challenges are now a thing your measuring (rs constant champions there)
Both failed as managers and where sacked in Spain previously as well just as another little comparasion.
Both good managers, both easy links to the Barca jobs, and both more proven than all 4 of Barcelons latest managers when appointed