Really? I'm due for an upgrade as my daughter is using my 2014 MBP for homeschooling. I've been debating this very train of thought and would love to know why you feel this way.
Let me give you my workflow.
-I can use Word, Excel, Powerpoint via my 365 subscription. MS did a great job with the iPadOS version of these apps.
-Safari is great on iPad. So my browsing needs are satisfied.
-I can draw easily with the Appl Pencil using Procreate. This is much better on iPads obviously. No need for a Wacom or anything.
-iPadOS has mouse and trackpad support. The new keyboard has a built-in trackpad
-iPadOS has support for keyboard shortcuts so I can still do things like Alt Tabbing to switch apps.
-I can use the Split View for viewing multiple apps at once.
-Apple Shortcuts lets you create some rather neat automations.
My MBP is getting dusty. I'll still keep it as a redundant machine, though. But I don't use it anymore. I have a iMac as my primary machine.
However, with the pricing, unless your daughter is a big artist, I'd recommend the new Macbook Airs. Getting a kitted up iPadPro, Pencil 2.0, and keyboard is pricey.
It's biggest killer app is the drawing features with the apple pencil.
There is a cheaper option. You can get the "regular" iPad. It starts at 329 and supports the keyboard and pencil 1.0.
There's also the iPad Air is you need slightly better screens, camera and better internals.
You can always test drive and return it. Apple has a 14-day return policy.