Why are transformer based oscilloscope probes not common?

It should be possible to put a miniature 10:1 signal transformer at the probe tip, and connect it straight to the 50ohm input of the oscilloscope to create a 10X differential probe.

I would imagine some advantages:

• High impedance at high frequencies.
• DC isolation allows high voltage probing.
• Less expensive than active probes.
• Functional over a wider temperature range, allowing measurements inside environmental chambers.

And one significant disadvantage:

• Only usable on DC balanced signals, such as Ethernet, PCI-Express, and similar. Probably useful for some RF measurements as well.

What am I missing?

Why are transformer based oscilloscope probes not common?

It should be possible to put a miniature 10:1 signal transformer at the probe tip, and connect it straight to the 50ohm input of the oscilloscope to create a 10X differential probe.

I would imagine some advantages:

• Poor mans differential probe.
• High impedance at high frequencies.
• DC isolation allows high voltage probing.
• Less expensive than active probes.
• Functional over a wider temperature range, allowing measurements inside environmental chambers.

And a couple of disadvantages:

• Bandwidth limited to approximately 1~500MHz.
• Only usable on DC balanced signals, such as Ethernet, PCI-Express, and similar. Probably useful for some RF measurements as well.

What am I missing?