Dashing into a high momentum arc swing or relatively small, brief hitbox will probably get you killed more often than it works.
Marth approach is done mostly on the ground because you retain some crucial fallback options after dashing forward like, say, shield, grab, jump (including jump back, which allows you to protect space with your aerials which adds another dimension to his defense & offense), dash attack, dash away (if dash dancing), dash cancel into his whole ground moveset (if space permits - this is big because d-tilt is crazy good for threatening and pressuring ground-based movement camps).
Marth is scary because his sword threatens in a manner that requires your foe kind of play around it in advance or else they risk being caught in a vulnerable grabbable or airborne position wherein you turn characters into sushi with your combo skills. We can take advantage of this to put pressure on people without actually needing to swing much. The upside to this is that disrespect strategies tend to attempt to play against your refusal to swing by taking positional liberties. At which point all you do to beat this is, well, swing at the foe for being in a bad position.
