He's a top class finisher without the nouse the outwit defenders.
Sure... he can out-pace them or out-dribble them. But he can't win the mental game against them with clever movement. His first instinct is always towards the ball rather than away from his marker. Assuming such a thing as a 'natural position' exists, Martial's is not as a centreforward whose main opponent is the other team's centreback.
If Spurs are buying him to replace Kane, they'll need to radically change their style of play. Same applies if Inter want him to replace Lukaku. The differences are greater than the similarities.
So I don't see either as viable options, tbh. I think a more realistic destination would be somebody looking for a wide forward. Which happens to be Manchester United for at least the next couple of months. I think Martial is probably going to stay until January.