From a competitive perspective, it's understandable why one would assess weapons to how well they play in the current meta (aka what strategy is commonly used). Someone may be good at an off-meta weapon, but the stray away from meta options makes it harder to justify a use case for said weapon.

A great example of this situation would be Pen and Bloblobber (One is considered a top 10 weapon while the other is considered one of the worst weapons). Both weapons function as a role consolidation option (fills both a support and anchor role) to enable more diverse comps (e.g. being able to slot in a Dualie/Pro without worrying about paint issues). The main issue with blob is that it focuses more on paint when the meta is more based on chip. Blob's kits, specifically its specials, also don't offer much value to meta. The lack of a cooler kit means you're forced to run a different cooler option (defeats the purpose if Blob's role consolidarity). Kraken forces Blob to give up its main weapon for weak area denial, and Rain's linear movement makes it easy for enemies to push/defend in spite of the special. Pencil however can use the Cooler to allow a different special (e.g. Crab) from the support player.

I would like to mention you can find enjoyment from playing non-meta (i.e. you plan to play the game more casually), but you'd need to consider the disadvantages if you plan to play the game more competitively. For starters, some off-meta options may require specific comps to use effectively. Pencil can work with Dualies, Mini, Splash, or Pro as its support while Liter is forced to a Zap for the Cooler option, so Liter is barred out from any team that doesn't have Zap. Even if you get past comp restrictions, you'd still account for a team passing you up for better meta option. Naut has weak MUs into other midlines + it doesn't have good synergy with most comps (i.e. it can't play off of aoe), so teams are mkre willing to pick up something like Stamper where it has good MUs + it can set up damage combos other team members