Does hypotension affect male erections?

Yes. Men require an ample blood suply and pressure to achieve and maintain an erection.Low blood pressures from medicines or decrease blood suply from atherosclerosis may compromise sexual function.
Yes. Many circulatory conditions affect erections: hypotension, hypertension, arterial disease, neurological disease, and the drugs used to treat them. "hypotension" is not the same for everyone, and many function normally (including sexually) at low blood pressures.