Spore counters almost everything as there aren't any grass types in natdexag. Moody just charges for a while then you can Baton Pass. Or you could use Shell Smash and sweep. So how viable is it?
Smeargle fits only on hyper offense teams with powerful sweepers that can capitalize on the opposing team's dropped Speed and threaten Defoggers, most importantly Ho-Oh. Swords Dance Mega Rayquaza works exceptionally well with Sticky Web support, as it can break most walls with ease after one boost and outspeed all grounded Pokemon with Sticky Web up. Eruption Primal Groudon and Water Spout Primal Kyogre are also major beneficiaries of Sticky Web, as the Speed drop in conjunction with their naturally terrifying wallbreaking prowess heavily limits traditional counterplay through revenge killers. Primal Groudon is an especially great teammate, as it can further support Sticky Web teams with Stealth Rock. Arceus-Ghost can spiral out of control very easily under Sticky Web due to its lack of sustainable checks and ability to outspeed faster threats such as Zacian-C and Eternatus. Arceus-Ghost also significantly improves the matchup against Ditto and can serve as a spinblocker. Other wallbreakers that enjoy Sticky Web support are Swords Dance Arceus-Ground, Calm Mind Kyogre and Arceus-Water, Dragon Dance Necrozma-DM, and Ultra Necrozma. Furthermore, having a late-game cleaner that doesn't rely too much on Sticky Web is also crucial to the playstyle's success, giving a backup plan for when Smeargle fails at setting up Sticky Web. As such, the likes of Yveltal, Swords Dance Zacian-C, Xerneas, and Mega Mewtwo Y are great teammates as well. Taunt Yveltal is particularly effective due to heavily threatening builds with support Arceus formes as the Defogger and preventing Ho-Oh's Defog.
Smeargle is a threatening Baton Pass user, especially if the opponent does not have any countermeasures to Spore or phazers.
Smeargle can function as a lead, but it is often even more threatening late-game when the opponent's team is weakened and entry hazards are up.
Smeargle's boundless movepool allows it to take on the role of a threatening late-game sweeper, despite its subpar offensive stats.
Source
It seems pretty good at a variety of roles.
Hope I helped!
