No.

One / you don't need mediumformat cameras systems.

It is most likely an overkill and costs a little fortune once you are hooked in it.

Albeit it even costs a fortune with pro lenses and high level fullframe cameras. Thinking mainly of Canon and its prices of their PRO "L" lenses, which are pretty steep. Even their top cameras are rather pricey.

Now there is of course a visual difference between mediumformat and Micro Four Thirds. Especially since brighter Fujifilm GF lenses have been created. Something is also something about the graduation of tones in the background of mediumformat images. As well the color fidelity when the file is getting stressed.

However, when comparing Micro Four Thirds with Fullframe camera images - the difference is (sometimes) less than what you would expect.

Here i focus primarily on portraits.

Micro Four Thirds camera systems

The above photo I made with the "tiny" sensor camera Olympus OM-1. And yet, I often absolutely love to work with that camera platform. And do sometimes create wonderful images with it. And boy do I love to do macro with it, just to name one area of special interest.

Taking portraits with let's say the Olympus M.Zuiko 45mm ƒ1.2 PRO lens - equivalent to a 90mm portrait lens - shows surprisingly major background blur, while the main motive - the face - remains sharp, even at wide open aperture of ƒ1.2

So, despite the "little" sensor - way smaller than a big Fujifilm GFX (33x44mm) sensor - you can do wondrous things with an Olympus camera and its PRO lenses. I've always felt from the day i started to buy the PRO ƒ 1.2 lenses - it suddenly gave the micro four thirds camera platform a level of higher quality. Images that stood out more than they did before. Which I had not seen with the smaller pancake lenses (since those create a lot less background blur, of course).

Yeah I know. I am a sucker for background blur. So, the PRO ƒ1.2 lenses, really made it far more easy, to create images with looked more in line with fullframe camera lenses / on fullframe camera bodies. The difference between fullframe vs micro Four thirds (+ ƒ 1.2 lenses) - were often far less than what I had expected.

Noise - is not an issue

When it comes to noise from a smaller sensor - which isn't really a big problem at all at low ISO. But when you have noise from such images, you can so easily clean it up with the Photoshop AI noise reduction. It just works to great - that images from a Micro Four Thirds camera really don't pose any problems in terms of quality and noise.

Sensor size is so much less of a problem today. I would say, it is not problem what so ever.