I like Breer's take. To put it into perspective, since 2012 we've drafted Omar Bolden, Philip Blake, Max Garcia, Devonte Booker, Josey Jewell and DaeSean Hamilton with our 4th round draft picks. We rarely even HAVE 4th round picks because we typically trade them off.
With keenum, we've gotta act now. We HAVE to draft a QB because we won't have one in 2020. With Flacco, we've got a lot of options. We can draft someone this year if we choose, draft someone next year, ect... We aren't on the hook for anything so if he doesn't work out, we could cut him the day after we sign him with zero penalty.
It's a very low risk move, worst case scenario we're missing out on the next Devontae Booker lol...