What is Dexterity (Acrobatics) good for? and merits of Bladesong?

[Arandur]

Trying to evaluate the merits of the Bladesinger subclass (Tasha's update). If you have a gish of another type (Hexblade, Eldritch Knight, etc), you can often take heavier armor and a shield, which are always-on as opposed to the limited number of Bladesong opportunities (Prof bonus per long rest). Are the other benefits of it worth it? What is the Advantage on Dexterity (Acrobatics) really good for?

For one, I've struggled to find any uses for Dexterity (Acrobatics), except to get out of grapples (rare, and other more surefire ways out, like teleport effects and forced movement).

What can you actually do with Acrobatics?
It seems it's heavily nerfed in 5e compared to previous editions. Can't use it to kip up from prone, cross difficult terrain, tumble for better AC or mobility-lite effects avoiding OAs, or even moving through a character or enemy's space. It seems reduced almost entirely to flavor.

Are the other Bladesong benefits really worth it?
+10ft speed seems good, but you need to be able to disengage easily, which you need level 6 Extra Attack + Cantrip of Shocking Grasp to do to avoid OA, or some multiclass combo or feat like Mobility.
As mentioned before, the INT bonus to AC is underwhelming compared to other gish options, unless you have high Dex and Int or are able to pick up the new Barrier tattoo at AC15 or higher.
The Concentration boost is nice, but there are other ways to achieve similar, with Resilient or Warcaster, Blade Ward cantrip combo at level 6, or assistance from friends/multiclassing (Resistance cantrip, Talisman).

Getting it for only a few combats a day, taking a Bonus Action to go into, and possibly running out during boss battles could really reduce its utility. If the purpose is really to create a melee wizard, I think it still kinda fails just on that basis -- you can't use it all the time.

[JNAProductions]

An important thing to remember, is that it's a Bladesinger Wizard, not a Bladesinger Wizard.

You're one of the most versatile and powerful full casters in the game. If you also got consistent melee options that outshone a Fighter, well, that'd be OP.

I do not own Tasha's yet, so don't know the exact mechanics, but figured I'd say that anyway.

Also, just because there's no explicit rule that lets you navigate difficult terrain quickly with acrobatics, does not mean you can't do it. You'll just need to chat to the DM about it.

[Evaar]

Okay so your party is facing a dragon that's flying around and strafing you with breath attacks.

First you tell someone else to cast Enlarge on your Barbarian and tell the Barbarian to be ready to catch.

Then you cast Warding Wind on yourself. Either with Contingency or an action you Ready on the next turn, you cast Dimension Door to land yourself on the dragon's back.

When you do that, you're going to need to succeed at an Acrobatics check to stay there. Good thing you put up Bladesong and you have a solid score in it, so you're very likely to succeed at that check.

Warding Wind creates an area of strong wing around you. Strong wind is a game-defined term that requires flying creatures to land or fall prone. So this dragon is going down as your own personal cyclone throws off its flight and sends it crashing to the ground.

You'd go with it, but fortunately you prepared Feather Fall for just such an occasion.

After your Barbarian picks their jaw up off the ground, they run over to Grapple the dragon.