A significant difference of the solar gravitational lens from a conventional telescope is that the gravitational lens telescope is not in any practical sense pointable.
For the telescope at a distance F from the sun to be re-aimed to image a new target 1° away, it would have to move a distance of (π/180°)F, which is 10 astronomical units at the minimum focal distance-- a lateral distance equivalent to the distance from Earth to Saturn.
This means that, in practice, such a telescope is not able to be repointed.
Thus, a telescope at the gravitational focus is necessarily going to be a singlepurpose telescope, with the target of observation selected before the mission is launched.
A gravitational focus mission can’t be used as a telescope to search for a target: such a mission must be with the objective to observe a target whose position is already known.
Geoffrey A. Landis, NASA John Glenn Research Center
https://www.nasa.gov/general/thin-film-isotope-nuclear-engin...
> The basic concept is to manufacture thin sheets of a radioactive isotope and directly use the momentum of its decay products to generate thrust.
Actually it's mentioned at the end of the article:
> Novel ability to reach deep space (> 150 AU) very quickly and then continue aggressive maneuvers (> 100 km/sec) for dim object search/rendezvous and/or retargeting telescopes at the solar gravitational focus over a period of years.
It doesn't scale well. The probe would be able to observe a carefully chosen extrasolar planetary system in the opposite direction in relation to the sun. If you want to observe a second system, it's necessary to launch a second probe 550 AU in another direction. You can't change targets just by rotating the probe, given its lens is the sun.