The GeForce 4 generation as a whole, while being solid enough cards, were historically not interesting. They were just basic spec bumps over the GeForce 3. No new features or similar. And, critically, the 9700 Pro released the same year as the GeForce 4 and absolutely smoked the living shit out of it.
And the 4 MX versions were GeForce 2 MX based IIRC. 3 was expensive.
The MX440 allowed players that were playing games on id Tech 3 to finally play at high frame rates. I remember this card being all the rage back then in pro gaming circles for this reason.
The MX440 was an entry level budget card? If it was all the rage in pro gaming circles at the time that's really just a reflection of how poor pro gamers were back then rather than anything to do with the MX440 being particularly noteworthy.