Was it because they hoped that they would eventually regain Berlin or was there a more strategic reason?
Hi, not discouraging further answers, but you may find these answers helpful:
https://old.reddit.com/r/AskHistorians/comments/95ubmf/why_was_bonn_chosen_to_be_the_capital_of_west/e3vnpe0/ by u/kieslowskifan
https://old.reddit.com/r/AskHistorians/comments/777o4y/on_20_june_1991_the_reunified_german_bundestag/dojnvmq/ by u/commiespaceinvader
https://old.reddit.com/r/AskHistorians/comments/6uhzhz/why_did_west_germany_choose_the_city_of_bonn_as/dlt166t/ by u/kieslowskifan