Yes, but its not totally true.
Chizuru is a better brute force, lets see bartz ATK with the best equip:
Bartz 6 Star
FFBEDB Unit Calculator
Right Hand: Sakurafubuki +98ATK
Left Hand: Kaiser Knuckles +101ATK
Head: Black Cowl +28ATK+25DEF+25SPR+100%Sleep
Body: Brave Suit +51DEF+15%ATK+15%MAG
Accessory 1: Champion's Belt +30ATK/DEF & 20%ATK/DEF w/ Fist weapon
Accessory 2: Champion's Belt +30ATK/DEF & 20%ATK/DEF w/ Fist weapon
Ability 1: Dual Wield Equip two single handed weapons
Ability 2: Power of Creation +30% ATK +30% MAG
Ability 3: Lunge Combo +10%MP+20%ATK+20%DEF
Ability 4: Blade Mastery +50% ATK Katana
Esper: Ifrit HP:4500 MP:2200 ATK:5100 DEF:2800 MAG:2100 SPR:2100
Total Stats: HP: 4523 MP: 200 ATK: 662 DEF: 374 MAG: 210 SPR: 175
While chizuru 6 star i can calculate:
Base: 154 (188)
Passives (ATK+20% and katana master 25%) : 69,3 (84,6)
Sakurafubuki x2: 196
Black Cowl: 28
Brave Suit: 23,1 (28,2)
Bracer: 30
Genji Glove: 15,4 (18,8)
Blade Mastery: 77 (94)
Power of creation: 46,2 (56,4)
ATK+20% x2: 61,6 (75,2)
Ifrit: 51
Total: 751,6 ATK
And thats without pots, with pots, bartz can get 731 ATK, while Chizuru with pots can reach 850 ATK... Thats insanelly high for chizuru, it even gets 2 ATK down compared to gilgamesh (852 ATK) a base 5 star.
But in versatility, chizuru is just a damage dealer and thats it. It doesnt have any elemental damage, it dont have auxiliary skills, and cant equip any kind of magic. Its just a very strong truck that hits hard.
While bartz has sacrifice (his star skill), entrust (ideal to accelerate Cecil's lv25 lb) and has wind resistance down. Also he can equip lv5 white/black/green magic.
If you only compare damage. Chizuru is top tier... the second best in the game (and only short by 2 ATK), while bartz is more versatile, and still in the damage department, he can do respectable damage.