jolting against marth's arent advised anywhere except for long distances, marth can close most distances surprisingly fast with that sword of his.
but hey i go against a marth who knows how pikachu plays, most marths wont know what to do against barrages of thunder jolts
*Ok have enough time to post some lovely Marth advice <3
Marth might be intimidating and all with that big *** sword of his with the godlike tip, but he is even more intimidating then that. :D
Luckily your a nimble little pikachu, two main options can be applied; camping until he approaches you, or playing an aggressive bait style. All your trying to do is as this lovely gentleman above me said is to bait any attack waiting for the lag, dtilts not included those things are fast. If you are in a position where your vulnerable get your tail either as far away as possible, or get as close as possible where your tiny arms can reach and beat his smexy out of him. Pikachu is combo fodder for marth for the first 70%, then after that you mess up marths game. When you get to high percents, then more options arise; you could still play defensive and wait for Marth to attack first, but now you can also run in on marth without fear of being combo practice, just watch out for the tip of his prince sword. Wave dashing out of shield is also a nice thing to know because if you block marths fsmash, just wavedash then usmash.
Marth is only as complicated as you make him, there aren't many super amazing Marth's your probably gonna face or out there in general(except if you live next to M2K). I feel that Marth players are all the same nowadays, and many make the same mistakes. Just play smart and things will most likely work out in the end.