In general you will find a great deal of distaste for bridge cameras here and on most photography forums. In a few unique circumstances they can be good options (very inexpensive super zoom) but for most people they aren't recommended.
Sensor size is a big deal
Why not get a bridge camera? Since they were introduced and became somewhat popular, the market has generally moved past them for one main reason. The sensors that most bridge cameras have are tiny and not well suited to the demands of today's digital photographers. The sensor that you will find in a standard bridge camera is similar in sized to what you will find in a regular smartphone of today. In other words, beyond having a physical optical zoom and some dedicated buttons, you really aren't getting much else beyond what most people already carry in their pockets.
You are right that the Nikon D70 is showing its age. But it still has the ability for interchangeable lenses which makes it somewhat capable even compared to a bridge camera of today.
To compare, the Sony bridge camera you are looking at has an image sensor of 6.17 x 4.55 mm (1/2.3") in size. The Nikon D70 has an image sensor of 23.7 mm × 15.6 mm.
What I would recommend
If you really want better quality, but can't spend much more, you are going to be severely limited in your options. I would advise a used model that is 2-3 generations old. The D70 is 7 generations old currently so it is showing its age. If you don't feel the need to stick with a DSLR(which I don't think you necessarily need to either), I would advise looking at mirrorless camearas such as the Sony RX-100 (1st generation), which you can get in your price range and still take excellent shots with. Note that some but not all mirrorless cameras do offer much larger sensors compared to the bridge camera you are looking at, plus of course could be purchased with features of a much newer camera.
Conclusion
So, in the end; only you can determine what is the best camera for you and your budget. But be aware that you will find a largely negative impression of bridge cameras here and on similar websites when comparing these two cameras due to the sensor size.
See also:
- What are the differences between a bridge camera and a DSLR?
- Are there compact cameras with large sensors?
Note: some people consider mirrorless cameras bridge cameras too. In my answer I am considering them separate lines.