The problem with optimization...

“What gets measured gets managed — even when it’s pointless to measure and manage it, and even if it harms the purpose of the organisation to do so”

https://medium.com/centre-for-public-impact/what-gets-measured-gets-managed-its-wrong-and-drucker-never-said-it-fe95886d3df6

Utility doesn't show up in spreadsheets.

Optimizers focus on the attributes they care about?

Damage per round (DPR), AC, saving throw proficiency, and hit points are easy things to show/track in a spreadsheet but they don't tell the whole story.

Features like Tough grant up to 40 hit points to a character -- and it's often taken as a feat very late in a character's progression -- to make a character look stronger than it functions. Gaining that many hit points, specifically at level 19 or 20 doesn't do much besides inflate a number that can be seen; the character is unlikely to even get there and there are better feats you can take that don't show up (e.g. Lucky, Ritual Caster, Inspiring Leader).

We can cheese hit points -- A Hill Dwarf Draconic Sorcerer with Tough (and 16 CON) has 222 hit points. A level 20 fighter with 16 CON has 184 hit points and a level 19 barbarian with 16 CON has 195 (at level 20, the 16 CON turns into 20 CON, so it spikes to 245.... but dumping CON back down to 16 gives a barbarian 205 hit points at 20). The problem with this cheese is that the same sorcerer can only heal themselves for 1d6+3 per hit dice (20 * 6.5 = 130 average healing) and while the barbarian heals for 1d12+3 (20 * 9.5 = 190 average healing)... and it doesn't consider damage resistances the barbarian might have when it takes damage.

Successful Concentration Saves Increases Your Damage

So does not dying...

Expending Resources is also Bad

Most tables don't follow the adventuring day guidelines in the DMG, so you're probably going to get more rests per day than you should but that shouldn't be a pass for sheet damage to ignore tougher adventuring days.

The X-Men Problem

When a character is disproportionally stronger than the rest of the party, the player is a threat to the party.

The premise of X-Men deals with humans trying to retain power over mutants even though the mutants are more powerful -- good mutants aren't necessarily a problem but mutants with bad intentions are problems to both humans and mutants. This same principal applies to roleplaying games -- if one player is disproportionally strong (or weaker) than the rest of the party, they become a target. The party is potentially one Dominate Person away from at least one player death.