I'm not sure Arsenal will win easily --- in betting it will probably do in BTTS rather than winning in one of them, still quite hesitant for Arsenal despite playing at home.
The two teams are close to each others in terms of points and performance right now. It is true that the results of Newcastle United are quite better for the moment than gunners but at the end there isn't a lot of difference between them and both teams have a good chance to win.
Newcastle United are in less comfortable position compared to gunners which almost secured the UEFA Champions League spot so they might end up winning it or a very possible draw could happen with both teams scoring.