Two-weapon fighting is itself, not worth it. Straight out of the box, using a two-handed weapon does better damage. See this question for details. By the time you add in the damage boost from the Great Weapon Master feat, a two-handed weapon crushes two-weapon fighting completely.
It ges worse for two-weapon fighting, though, because the whole benefit of two-weapon fighting is being able to attack with a bonus action in addition to your regular attacks. However, a two-handed weapon (glaive or halberd) can do that anyway, thanks to the Polearm Master feat.
For most characters, getting both these feats is a little impractical. But as a variant human, you get a feat right out of the box, and as a Fighter, you get extras along the way. So this is completely attainable.
Everything above is optimization advice. A two-handed weapon does far better damage than two-weapon fighting, but if you want to use two-weapon fighting, you should go for it.
Now, the question you really wanted to know - is attacking with your action and then with a bonus action worth it, since you can cast a spell with your action and then attack with your bonus action?
And the answer is yes, absolutely. Attacking will usually be a better use of your action than casting a spell. For example, at level 13, you could cast fireball for 8d6 damage, averaging 28 damage. However, if you instead attacked with your action, you could attack 3 times, dealing 1d10 + 15 damage each time - for an average of 61.5 damage - more than twice as much.
This assmes that you're using the advice I gave above. If you're dual-wielding, you could attack 3 times for 1d8 + 5 damage, averaging 28.5 damage. Still better than casting fireball, but only just.
So why use spells? Well, the easiest example is casting haste on yourself, giving you an extra attack every round, as well as some other benefits. But you're likely to do that on the first round of a combat, and then spend the rest of the time attacking.
