Yes it is sufficient, repeat, no it is insufficient. The answer depends on what you want to observe. Give us a clue about that and we will be able to give a more personalised answer.
This question has been asked and answered many many times on this forum. Looking at the answers will help you understand what questions you need to ask and answer before we can help you more.
In the absence of such info, it is worth noting that surplus 20MHz analogue scopes are commonplace. My local hackspace has more than it needs; yours might too.
Only buy one if it is fully guaranteed and cheap.
Any scope is better than none, but with a little imagination you can do a hell of a lot with a multimeter, some switches, a variable PSU, and some LEDs.
The one area where an analogue scope is not sufficient is if you neet to observe one-off events; there a digital scope is highly beneficial.